feat: switch to semantic-release for npm publishing

- Remove old manual npm publish workflow
- Add semantic-release, @semantic-release/changelog, and @semantic-release/git as dev dependencies
- Configure semantic-release in .releaserc.json to publish to npm and commit CHANGELOG.md back to repo
- Add new semantic-release.yml GitHub Action triggered on main branch
- Upgrade to Node 20 and v4 GitHub actions in workflow

Co-authored-by: johndc7 <16856554+johndc7@users.noreply.github.com>

Author: google-labs-jules[bot]

.github/workflows/npm-publish.yml

@@ -0,0 +1,37 @@
+name: Release
+
+on:
+  push:
+    branches:
+      - main
+
+jobs:
+  release:
+    runs-on: ubuntu-latest
+    permissions:
+      contents: write
+      issues: write
+      pull-requests: write
+      id-token: write
+
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@v4
+        with:
+          fetch-depth: 0
+          persist-credentials: false
+
+      - name: Setup Node.js
+        uses: actions/setup-node@v4
+        with:
+          node-version: 20
+          registry-url: 'https://registry.npmjs.org/'
+
+      - name: Install dependencies
+        run: npm ci
+
+      - name: Semantic Release
+        env:
+          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+          NPM_TOKEN: ${{ secrets.NPM_TOKEN }}
+        run: npx semantic-release

.github/workflows/semantic-release.yml

@@ -0,0 +1,23 @@
+{
+  "branches": [
+    "main"
+  ],
+  "plugins": [
+    "@semantic-release/commit-analyzer",
+    "@semantic-release/release-notes-generator",
+    "@semantic-release/changelog",
+    "@semantic-release/npm",
+    "@semantic-release/github",
+    [
+      "@semantic-release/git",
+      {
+        "assets": [
+          "CHANGELOG.md",
+          "package.json",
+          "package-lock.json"
+        ],
+        "message": "chore(release): ${nextRelease.version} [skip ci]\n\n${nextRelease.notes}"
+      }
+    ]
+  ]
+}