fix(ci): use bash parameter expansion to extract first commit line

Author: DmitriyLewen

.github/workflows/release-please.yaml

@@ -76,7 +76,7 @@ jobs:
           COMMIT_MESSAGE: ${{ github.event.head_commit.message }}
         run: |
           # Take only the first line to avoid git trailers (e.g. Co-authored-by) breaking $GITHUB_OUTPUT
-          FIRST_LINE=$(echo "$COMMIT_MESSAGE" | head -1)
+          FIRST_LINE=${COMMIT_MESSAGE%%$'\n'*}
           echo "version=$( echo "$FIRST_LINE" | sed 's/^release: v\([0-9]\+\.[0-9]\+\.[0-9]\+\).*$/\1/' )" >> $GITHUB_OUTPUT
           echo "pr_number=$( echo "$FIRST_LINE" | sed 's/.*(\#\([0-9]\+\)).*$/\1/' )" >> $GITHUB_OUTPUT
           echo "release_branch=release/v$( echo "$FIRST_LINE" | sed 's/^release: v\([0-9]\+\.[0-9]\+\).*$/\1/' )" >> $GITHUB_OUTPUT