Rename checks workflow

To match other chesskit-app repos.

Author: pdil

.github/workflows/test-chesskit-engine.yml renamed to .github/workflows/checks.yaml

@@ -12,4 +12,4 @@ jobs:
     uses: chesskit-app/workflows/.github/workflows/check-swift-package.yaml@master
     secrets: inherit
     with:
-       test_bundle: ChessKitEnginePackageTests
+      test_bundle: ChessKitEnginePackageTests