Pin the docs workflow to Swift 6.3

Without a version the setup action installs the latest toolchain. Swift 6.4.0 shipped on 2026-09-15 and the swiftly build cached on the runner cannot install it, so the docs job started failing.
2026-09-16 21:01:26 +02:00
1 changed files with 1 additions and 0 deletions
@@ -26,6 +26,7 @@ jobs:
    - name: Set up Swift
      uses: swift-actions/setup-swift@v3
      with:
+        swift-version: "6.3"
        skip-verify-signature: true
    - name: Generate Docs
      run: |