check_end_of_line: add hook to check for EOL at EOF

Fixes #15.
Status Job ID Name Coverage
  External
passed kwrobot-branch-check

failed rust-git-hooks-megas-linux-debug

failed rust-git-hooks-megas-linux-debug

failed rust-git-hooks-megas-linux-debug

failed rust-git-hooks-megas-linux-debug

failed rust-git-hooks-megas-linux-debug

00:00:04