gitea: Update to 1.11.3

This release fixes three bugs.

Release notes: https://blog.gitea.io/2020/03/gitea-1.11.3-and-1.10.6-released/

Also fix LDFLAGS so that the version number (among other things) is built into
the binary correctly, and make the regexp used in the Makefile work with
bsdgrep (both thanks to adamw).

Will MFH due to bsdgrep build failure and stopwatch panic fix.

PR: 244898
Submitted by: maintainer
MFH: 2020Q1