Merge pull request #4317 from uklotzde/validate-metainfo-xml

GitHub CI: Validate AppStream metadata

.github/workflows/pre-commit.yml

@@ -21,7 +21,7 @@ jobs:
       run: sudo apt-get update && sudo apt-get install -y --no-install-recommends clang-format-10
 
     - name: "Detect code style issues (push)"
-      uses: pre-commit/action@v2.0.0
+      uses: pre-commit/action@v2.0.3
       if: github.event_name == 'push'
       # There are too many files in the repo that have formatting issues. We'll
       # disable these checks for now when pushing directly (but still run these
@@ -30,7 +30,7 @@ jobs:
         SKIP: end-of-file-fixer,trailing-whitespace,clang-format,eslint,no-commit-to-branch
 
     - name: "Detect code style issues (pull_request)"
-      uses: pre-commit/action@v2.0.0
+      uses: pre-commit/action@v2.0.3
       if: github.event_name == 'pull_request'
       env:
         SKIP: no-commit-to-branch
@@ -53,3 +53,10 @@ jobs:
       with:
         name: ${{ env.UPLOAD_PATCH_FILE }}
         path: ${{ env.UPLOAD_PATCH_FILE }}
+
+    - name: "Install appstreamcli"
+      run: sudo apt-get update && sudo apt-get install -y --no-install-recommends appstream
+
+    # AppStream metadata has been generated/updated by a pre-commit hook
+    - name: "Validate AppStream metadata"
+      run: appstreamcli validate res/linux/org.mixxx.Mixxx.metainfo.xml