Update deploy.yml to run build on PRs

Include Posthog API key as an env variable.

.github/workflows/deploy.yml

@@ -4,6 +4,8 @@ on:
   # Runs on pushes targeting the default branch
   push:
     branches: ["main"]
+  pull_request:
+    branches: ["main"]
 
   # Allows you to run this workflow manually from the Actions tab
   workflow_dispatch:
@@ -22,7 +24,7 @@ concurrency:
 
 env:
   BUILD_PATH: "." # default value when not using subfolders
-  # BUILD_PATH: subfolder
+  POSTHOG_API_KEY: ${{ secrets.POSTHOG_API_KEY }}
 
 jobs:
   build:
@@ -62,6 +64,8 @@ jobs:
       - name: Install dependencies
         run: ${{ steps.detect-package-manager.outputs.manager }} ${{ steps.detect-package-manager.outputs.command }}
         working-directory: ${{ env.BUILD_PATH }}
+      - name: key
+        run: echo "${{ env.POSTHOG_API_KEY }}"
       - name: Build with Astro
         run: |
           ${{ steps.detect-package-manager.outputs.runner }} astro build \
@@ -74,6 +78,7 @@ jobs:
           path: ${{ env.BUILD_PATH }}/dist
 
   deploy:
+    if: github.ref == 'refs/heads/main' || github.event_name == 'workflow_dispatch'
     environment:
       name: github-pages
       url: ${{ steps.deployment.outputs.page_url }}