Log Message:
Update to 6.60

Upstream changes:
6.60      2021-12-17 22:29:57Z
    - Warn if updating modification time of mirrored file fails (GH#399) (Ville \ 
Skyttä)

6.59      2021-12-02 21:16:04Z
    - Use American English aspell master dictionary for POD spelling tests \ 
(GH#394) (Ville Skyttä)
    - Remove unnecessary string concatenations in mirror error messages (GH#391) \ 
(Ville Skyttä)
    - Spelling and grammar fixes (GH#390) (Ville Skyttä)