test against PHP nightly

- build against PHP nightly on PR and daily schedule
- use setup-php for linux builds (which drops Alpine builds)

.github/workflows/build.yml

@@ -16,21 +16,23 @@ jobs:
       fail-fast: false
       matrix:
         php: ['8.0', '8.1', '8.2', '8.3']
-        os: ['debian', 'alpine']
-    container:
-      image: ghcr.io/open-telemetry/opentelemetry-php-instrumentation/php:${{ matrix.php }}-${{ matrix.os }}-debug
 
     steps:
-      -   uses: actions/checkout@v4
-      -   name: Build
-          run: |
-            phpize
-            ./configure
-            make
-      -   name: Test
-          env:
-            TEST_PHP_ARGS: "-q" #do not try to submit failures
-          run: make test TESTS=--show-diff
+      - name: Checkout
+        uses: actions/checkout@v4
+      - name: Setup PHP
+        uses: shivammathur/setup-php@v2
+        with:
+          php-version: ${{ matrix.php }}
+      - name: Build
+        run: |
+          phpize
+          ./configure
+          make
+      - name: Test
+        env:
+          TEST_PHP_ARGS: "-q" #do not try to submit failures
+        run: make test TESTS=--show-diff
 
   macos:
     runs-on: macos-latest

.github/workflows/nightly.yml

@@ -0,0 +1,30 @@
+name: Build and test against PHP nightly
+
+on:
+  push:
+  pull_request:
+    branches: [ main ]
+  schedule:
+    - cron: '37 5 * * *'
+
+defaults:
+  run:
+    working-directory: ext
+
+jobs:
+  nightly:
+    if: github.repository == 'open-telemetry/opentelemetry-php-instrumentation'
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+      - uses: shivammathur/setup-php@v2
+        with:
+          php-version: 8.4
+      - name: Build and test
+        env:
+          TEST_PHP_ARGS: "-q"
+        run: |
+          phpize
+          ./configure
+          make
+          make test TESTS=--show-diff