tests: fix the PR title check broken by the action bump to v6.1.1

Since v6.1.0 each line of the `types` input is treated as a regex
pattern auto-wrapped in `^ $` (amannn/action-semantic-pull-request#292),
so the trailing "# comment" became part of the pattern: the line
"bugfix # bug fixes" means regex ^bugfix # bug fixes$, which can never
match the type token in a PR title. Every PR has failed the "Lint PR"
check since the bump in db281a3.

Under @v4 the input was split on whitespace into plain strings, so
"bugfix # bug fixes" accidentally yielded the bare token "bugfix", which
matched. That accidental tolerance is gone in v6.

Fix: list each type as one bare line on the strip block scalar (`|-`),
as the v6 docs describe and as other repos pinning the same v6.1.1 SHA
do:
https://github.com/projen/projen/blob/main/.github/workflows/pull-request-lint.yml#L23-L30

Author: tzssangglass

.github/workflows/semantic-pull-request.yml

@@ -18,13 +18,13 @@ jobs:
         with:
           # Configure which types are allowed.
           # Default: https://github.com/commitizen/conventional-commit-types
-          types: |
-            bugfix # bug fixes
-            change # backward incompatible changes
-            doc # documentation changes including code comments
-            editor # code editor related configurations
-            feature # implementing a new feature
-            optimize # performance optimizations
-            refactor # code refactoring and other code rearrangement
-            style # coding style changes
-            tests # test suite changes
+          types: |-
+            bugfix
+            change
+            doc
+            editor
+            feature
+            optimize
+            refactor
+            style
+            tests