moving libtasn1 to gitlab

[Nikos Mavrogiannopoulos]

Hi,
 After quite some long time struggling with savanah, I think it is
time for libtasn1 to move to some more reasonable software hosting
environment. Unless there are better proposals or objects, I'll move
the project to gitlab (i.e., make the current mirror primary), which
will allow using merge requests, CI and issue tracking for
collaboration.

The new source code hosting will be at:
https://gitlab.com/gnutls/libtasn1/


regards,
Nikos