ci: split test and validate workflow

.github/workflows/test.yml

@@ -20,11 +20,6 @@ jobs:
       -
         name: Checkout
         uses: actions/checkout@v3
-      -
-        name: Validate
-        uses: docker/bake-action@v3
-        with:
-          targets: validate
       -
         name: Test
         uses: docker/bake-action@v3

.github/workflows/validate.yml

@@ -0,0 +1,45 @@
+name: validate
+
+concurrency:
+  group: ${{ github.workflow }}-${{ github.ref }}
+  cancel-in-progress: true
+
+on:
+  push:
+    branches:
+      - 'master'
+      - 'releases/v*'
+  pull_request:
+
+jobs:
+  prepare:
+    runs-on: ubuntu-latest
+    outputs:
+      targets: ${{ steps.targets.outputs.matrix }}
+    steps:
+      -
+        name: Checkout
+        uses: actions/checkout@v3
+      -
+        name: Targets matrix
+        id: targets
+        run: |
+          echo "matrix=$(docker buildx bake validate --print | jq -cr '.group.validate.targets')" >> $GITHUB_OUTPUT
+
+  validate:
+    runs-on: ubuntu-latest
+    needs:
+      - prepare
+    strategy:
+      fail-fast: false
+      matrix:
+        target: ${{ fromJson(needs.prepare.outputs.targets) }}
+    steps:
+      -
+        name: Checkout
+        uses: actions/checkout@v3
+      -
+        name: Validate
+        uses: docker/bake-action@v3
+        with:
+          targets: ${{ matrix.target }}