Invalid vCard date-time string

[the-djmaze]

DateTimeParser.php

Replace
Z | (?: \+|-)(?: [0-9]{2}:[0-9]{2})
Into
Z | (?: \+|-)(?: [0-9]{2}:?[0-9]{2})

Because some timezone entries are without the :

[staabm]

thx for reporting. feel free to provide a PR with an additional test-case covering the change

[the-djmaze]

I don't have an actual test-case yet, as it was only reported at
the-djmaze/snappymail#528

But will do a PR when i have the time.