refactor: Get current Git branch more simply

Use the new --show-current arg to branch in place of git rev-parse.

Author: Kurt-von-Laven

entrypoint.sh

@@ -7,7 +7,7 @@ if [ "$INPUT_COMMIT" == 'false' ]; then INPUT_COMMIT='--files-only'; else INPUT_
 if [ "$INPUT_COMMITIZEN_VERSION" == 'latest' ]; then INPUT_COMMITIZEN_VERSION="commitizen"; else INPUT_COMMITIZEN_VERSION="commitizen==$INPUT_COMMITIZEN_VERSION"; fi
 if [ -n "$INPUT_NO_RAISE" ]; then INPUT_NO_RAISE="--no-raise $INPUT_NO_RAISE"; else INPUT_NO_RAISE=''; fi
 
-CURRENT_BRANCH=$(git rev-parse --abbrev-ref HEAD)
+CURRENT_BRANCH="$(git branch --show-current)"
 INPUT_BRANCH=${INPUT_BRANCH:-$CURRENT_BRANCH}
 INPUT_EXTRA_REQUIREMENTS=${INPUT_EXTRA_REQUIREMENTS:-''}
 REPOSITORY=${INPUT_REPOSITORY:-$GITHUB_REPOSITORY}