Bump sersoft-gmbh/swifty-docs-action from 2 to 3

Bumps [sersoft-gmbh/swifty-docs-action](https://github.com/sersoft-gmbh/swifty-docs-action) from 2 to 3.
- [Release notes](https://github.com/sersoft-gmbh/swifty-docs-action/releases)
- [Commits](sersoft-gmbh/swifty-docs-action@v2...v3)

---
updated-dependencies:
- dependency-name: sersoft-gmbh/swifty-docs-action
  dependency-type: direct:production
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <[email protected]>

.github/workflows/docs.yml

@@ -76,7 +76,7 @@ jobs:
           key: ${{ runner.os }}-${{ steps.os-version.outputs.version }}-spm-${{ steps.swift-setup.outputs.version }}-${{ hashFiles('**/Package.resolved') }}
           restore-keys: |
             ${{ runner.os }}-${{ steps.os-version.outputs.version }}-spm-${{ steps.swift-setup.outputs.version }}-
-      - uses: sersoft-gmbh/swifty-docs-action@v2
+      - uses: sersoft-gmbh/swifty-docs-action@v3
         env:
           ENABLE_DOCC_SUPPORT: '1'
           DOCC_JSON_PRETTYPRINT: 'YES'