Add valhalla EA build

Author: rbygrave

.github/workflows/valhalla.yml

@@ -0,0 +1,41 @@
+name: Valhalla EA
+
+on:
+  workflow_dispatch:
+  schedule:
+    - cron: '39 2 * * 3'
+
+jobs:
+  build:
+
+    runs-on: ${{ matrix.os }}
+    permissions:
+      contents: read
+      packages: write
+    strategy:
+      fail-fast: false
+      matrix:
+        java_version: [valhalla]
+        os: [ubuntu-latest]
+
+    steps:
+      - uses: actions/checkout@v4
+      - name: Set up Java
+        uses: oracle-actions/setup-java@v1
+        with:
+          website: jdk.java.net
+          release: ${{ matrix.java_version }}
+      - name: Maven cache
+        uses: actions/cache@v4
+        env:
+          cache-name: maven-cache
+        with:
+          path:
+            ~/.m2
+          key: build-${{ env.cache-name }}
+      - name: Maven version
+        run: mvn --version
+#      - name: Prepare
+#        run: ./jakarta-to-valhalla.sh
+      - name: Build with Maven
+        run: mvn package