chore: add preview release

Author: mandarini

.github/workflows/preview-release.yml

@@ -0,0 +1,36 @@
+name: Preview release
+
+permissions:
+  pull-requests: write
+
+on:
+  push:
+    branches:
+      - master
+  pull_request:
+    types: [opened, synchronize, labeled]
+
+jobs:
+  preview:
+    if: >
+      github.repository == 'supabase/supabase-js' &&
+      (github.event_name == 'push' ||
+      (github.event_name == 'pull_request' && contains(github.event.pull_request.labels.*.name, 'trigger: preview')))
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout code
+        uses: actions/checkout@v4
+
+      - name: Setup Node.js
+        uses: actions/setup-node@v4
+        with:
+          node-version: '20'
+          cache: 'npm'
+
+      - name: Install dependencies
+        run: npm ci
+
+      - name: Build
+        run: npm run build
+
+      - run: npx pkg-pr-new@latest publish --compact

README.md

@@ -3,6 +3,12 @@
 - **Documentation:** https://supabase.com/docs/reference/javascript/start
 - TypeDoc: https://supabase.github.io/supabase-js/v2/
 
+<div align="center">
+
+[![pkg.pr.new](https://pkg.pr.new/badge/supabase/supabase-js)](https://pkg.pr.new/~/supabase/supabase-js)
+
+</div>
+
 ## Usage
 
 First of all, you need to install the library: