ci: only deploy on relevant code changes

.gitea/workflows/cd.yaml

@@ -9,6 +9,27 @@ env:
   DOCKER_REGISTRY: gitea.t000-n.de
 
 jobs:
+  check-changes:
+    name: Check changes
+    runs-on: ubuntu-latest
+    outputs:
+      changes: ${{ steps.filter.outputs.code }}
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+      - name: Get changes
+        id: filter
+        uses: dorny/paths-filter@v3
+        with:
+          filters: |
+            code:
+              - 'go.mod'
+              - 'go.sum'
+              - '**/*.go'
+              - 'config.example.yaml'
+              - 'Dockerfile'
+              - 'Makefile'
+
   test:
     name: test
     runs-on: ubuntu-latest
@@ -49,6 +70,8 @@ jobs:
         arch: [amd64, arm64]
     needs:
       - test
+      - check-changes
+    if: ${{ needs.check-changes.outputs.code == 'true' }}
     runs-on:
       - ubuntu-latest
       - linux_${{ matrix.arch }}