chore(deps): update davidanson/markdownlint-cli2-action action to v21

.gitea/workflows/golang-linters.yaml

@@ -26,4 +26,4 @@ jobs:
         go-version: ${{ matrix.go }}
     - uses: golangci/golangci-lint-action@v9.0.0
       with:
-        version: v2.6.1 # renovate: datasource=github-releases depName=golangci/golangci-lint
+        version: v2.5.0 # renovate: datasource=github-releases depName=golangci/golangci-lint

.gitea/workflows/markdown-linters.yaml

@@ -14,6 +14,6 @@ jobs:
     runs-on: ubuntu-latest
     steps:
     - uses: actions/checkout@v5.0.0
-    - uses: DavidAnson/markdownlint-cli2-action@v20.0.0
+    - uses: DavidAnson/markdownlint-cli2-action@v21.0.0
       with:
         globs: '**/*.md'