gitea: Update to 1.11.6

Update Gitea to 1.11.6

This release fixes two security issues and 14 bugs.

Release notes: https://github.com/go-gitea/gitea/releases/tag/v1.11.6

And despite /some/ work being done on the invalid Go template syntax for the
Wiki pages, the main bug has not been fixed and merged, so the patch still is
required.

PR: 246892
Submitted by: maintainer
MFH: 2020Q2
Relnotes: https://github.com/go-gitea/gitea/releases/tag/v1.11.6
Security: yes, see Relnotes