release tag ET_2020_05_v0 points to wrong commit in CTThorns

In CTThorns the release tag ET_2020_05 points to git hash d3c9278 "CT_MultiLevel: move LaTeX macros after THORNGUIDE marker" of ctthorns while the branch ET_2020_05 points to one extra commit git hash 8fae77a "CT_Analytic: regenerate using Kranc e69182c" of ctthorns.

At release time both tag and branch were supposed to point to the same commit.

This should be addressed by creating a v1 tag pointing to 8fae77a.