Fix tag date

Tags got the date of the oldest commit, while this should be the date of
 the newest commit.

src/RepoHandler/RepoHandler.php

@@ -238,7 +238,7 @@ public function fetchCommitData(bool $refresh): array
                 continue;
             }
 
-            $commitData[$tag]['date']     = $line[0];
+            $commitData[$tag]['date']     = $commitData[$tag]['date'] ?? $line[0];
             $commitData[$tag]['titles'][] = $line[1];
             $commitData[$tag]['hashes'][] = $line[2];
         }