- Downloads the new emoji data from emojibase
 - Compiles it into gtk format data
 - If there are changes:
   - Pushes a new commit to $EMOJI_MR_BRANCH
   - If there's not already a waiting MR, opens one against
     $TARGET_PROJECT_ID (defaults to $CI_PROJECT_ID).

This is supposed to work in a gitlab CI project schedule where a
repository-wide access token is exposed as masked variables (and visible
only to the protected branches) $REPO_ACCESS_TOKEN_NAME and $REPO_ACCESS_TOKEN.