Fix date command around DST switch
Fix date command around DST switch

TZ=Europe/Riga date -d 'Mar 31 03:34:31 2019 GMT' +%s
date: invalid date ‘Mar 31 03:34:31 2019 GMT’

TZ=Europe/Riga date -u -d 'Mar 31 03:34:31 2019 GMT' +%s
1554003271

sseemayer/dokku-letsencrypt,dokku/dokku-letsencrypt