[Feature] Allow `workflow_dispatch`

[boesing]

Feature Request

Q	A
New Feature	yes
RFC	yes
BC Break	no

Summary

I'd love to allow workflow_dispatch to manually trigger CI from github webinterface. It seems that it is not supported as of now since I receive the following error:

Unable to handle events of type workflow_dispatch; aborting

This is caused by the entrypoint.sh:

laminas-ci-matrix-action/entrypoint.sh

Lines 17 to 41 in 026cc55

	case $GITHUB_EVENT_NAME in
	pull_request)
	REF=$GITHUB_REF
	LOCAL_BRANCH=$GITHUB_HEAD_REF
	BASE_BRANCH=$GITHUB_BASE_REF
	if [[ ! $LOCAL_BRANCH || ! $BASE_BRANCH ]]; then
	echo "Missing head or base ref env variables; aborting"
	exit 1
	fi
	LOCAL_BRANCH_NAME=pull/${LOCAL_BRANCH_NAME}
	;;
	push)
	REF=${GITHUB_REF/refs\/heads\//}
	LOCAL_BRANCH=${REF}
	;;
	tag)
	REF=${GITHUB_REF/refs\/tags\//}
	LOCAL_BRANCH=${REF}
	;;
	*)
	echo "Unable to handle events of type $GITHUB_EVENT_NAME; aborting"
	exit 1
	esac