Downgrading to PHP7 compatibility

git.inc.php

@@ -44,7 +44,7 @@ function git_rev_from_commit_message(string $message) : string
   return $commit_hash;
 }
 
-function get_git_last_remote_tag(string $repo) : string|bool
+function get_git_last_remote_tag(string $repo) : mixed
 {
   $remote_tags = [];
   git_do($repo, 'ls-remote --tags origin', $output, false);
@@ -62,7 +62,7 @@ function get_git_last_remote_tag(string $repo) : string|bool
   return _get_last_version_tag($remote_tags);
 }
 
-function _get_last_version_tag(array $tags) : string|bool
+function _get_last_version_tag(array $tags) : mixed
 {
   if(!$tags)
     return false;