setup some release stuff (#100)

This sets up some stuff for release automation, built around github actions, changesets, and pkg.pr.new. 
- pkg-pr-new.yml: For every pull request, we publish a version to their registry, and a comment will popup in the PR comments showing how to use it (eg: cloudflare/workers-oauth-provider#99 (comment)) This lets people test out PRs before they even land. 
- prerelease.yml: whenever something lands in main, after Test(test.yml) passes, we publish to npm with `@beta`, with the version being the git hash. This lets people test whatever's in master quickly.  
- release.yml: When a PR lands after Test(test.yml) passes, the changeset action opens a Version Packages PR (if not already created), that deletes all changesets under the .changeset folder, and populates the CHANGELOG with their contents. You can edit the CHANGELOG further as you wish here. 
- release.yml: When the Version Packages PR itself lands, then the changesets action will do an npm release (with the highest common changeset level: path, minor, or major). It will also tag git and make a github release. 

You can make a changeset in 2 ways:
- running `npx changeset` in your PR branch, which will ask you a couple of questions (what level of change, and title). You can add more details directly in the generated changeset. You can add as many (or as few, even 0) changesets as you'd like. 
- Every PR will have a comment generated that shows what changesets are included (or if they're not). This will also have a link to generate and add a changeset to the PR directly (example cloudflare/workers-oauth-provider#99 (comment))

Author: threepointone

.changeset/README.md

@@ -0,0 +1,8 @@
+# Changesets
+
+Hello and welcome! This folder has been automatically generated by `@changesets/cli`, a build tool that works
+with multi-package repos, or single-package repos to help you version and publish your code. You can
+find the full documentation for it [in our repository](https://github.com/changesets/changesets)
+
+We have a quick list of common questions to get you started engaging with this project in
+[our documentation](https://github.com/changesets/changesets/blob/main/docs/common-questions.md)

.changeset/config.json

@@ -0,0 +1,14 @@
+{
+  "$schema": "https://unpkg.com/@changesets/[email protected]/schema.json",
+  "changelog": [
+    "@changesets/changelog-github",
+    { "repo": "cloudflare/capnweb" }
+  ],
+  "commit": false,
+  "fixed": [],
+  "linked": [],
+  "access": "public",
+  "baseBranch": "main",
+  "updateInternalDependencies": "patch",
+  "ignore": []
+}

.changeset/good-glasses-see.md

@@ -0,0 +1,5 @@
+---
+"capnweb": patch
+---
+
+Trigger a first release

.github/workflows/pkg-pr-new.yml

@@ -0,0 +1,27 @@
+name: Publish to pkg.pr.new for pre-release
+permissions:
+  contents: read
+
+on:
+  pull_request: {}
+
+jobs:
+  publish:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+        with:
+          fetch-depth: 1
+      - uses: actions/setup-node@v4
+        with:
+          node-version: 22
+          cache: "npm"
+
+      - name: Install dependencies
+        run: npm ci
+
+      - name: Build packages
+        run: npm run build
+
+      - name: Publish to pkg.pr.new
+        run: npx pkg-pr-new publish

.github/workflows/release.yml

@@ -0,0 +1,69 @@
+name: Release
+permissions:
+  contents: write # to create release (changesets/action)
+  issues: write # to post issue comments (changesets/action)
+  pull-requests: write # to create pull request (changesets/action)
+  id-token: write # to use OpenID Connect token for provenance (changesets/action)
+
+on:
+  workflow_run:
+    workflows: ["Test"]
+    branches: [main]
+    types: [completed]
+
+jobs:
+  release:
+    if: ${{ github.event.workflow_run.conclusion == 'success' && github.repository_owner == 'cloudflare' }}
+    timeout-minutes: 5
+    runs-on: ubuntu-latest
+    environment: release
+
+    steps:
+      - uses: actions/checkout@v4
+        with:
+          fetch-depth: 1
+
+      - uses: actions/setup-node@v4
+        with:
+          node-version: 24    # includes npm 11.5.1 or later, needed for trusted publishing
+          cache: "npm"
+
+      - run: npm ci
+      - run: npm run build
+
+      - id: changesets
+        uses: changesets/action@v1
+        with:
+          # The standard step is only to run `changeset version` but this does not update the
+          # package-lock.json file. So we also run `npm install`, which does this update.
+          # This is a workaround until this is handled automatically by `changeset version`.
+          # See https://github.com/changesets/changesets/issues/421.
+          version: npx changeset version && npm install
+          publish: npx changeset publish
+        env:
+          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+
+  prerelease:
+    if: ${{ github.event.workflow_run.conclusion == 'success' && github.repository_owner == 'cloudflare' }}
+    timeout-minutes: 5
+    runs-on: ubuntu-latest
+    environment: release
+
+    steps:
+      - uses: actions/checkout@v4
+        with:
+          fetch-depth: 1
+
+      - uses: actions/setup-node@v4
+        with:
+          node-version: 24    # includes npm 11.5.1 or later, needed for trusted publishing
+          cache: "npm"
+
+      - run: npm ci
+
+      - name: Modify package.json version
+        run: npx tsx .github/version-script.ts
+
+      - run: npm run build
+
+      - run: npm publish --tag beta

.github/workflows/test.yml

@@ -1,10 +1,12 @@
 name: Test
+permissions:
+  contents: read
 
 on:
   push:
-    branches: [ main ]
+    branches: [main]
   pull_request:
-    branches: [ main ]
+    branches: [main]
 
 jobs:
   test:
@@ -14,19 +16,19 @@ jobs:
       options: --user 1001
 
     steps:
-    - uses: actions/checkout@v4
+      - uses: actions/checkout@v4
 
-    - name: Setup Node.js
-      uses: actions/setup-node@v4
-      with:
-        node-version: '22'
-        cache: 'npm'
+      - name: Setup Node.js
+        uses: actions/setup-node@v4
+        with:
+          node-version: "22"
+          cache: "npm"
 
-    - name: Install dependencies
-      run: npm ci
+      - name: Install dependencies
+        run: npm ci
 
-    - name: Build project
-      run: npm run build
+      - name: Build project
+        run: npm run build
 
-    - name: Run tests
-      run: npm test
+      - name: Run tests
+        run: npm test