add event entry for 2021-07-26 at GFZ

8 jobs for add-GFZ-half-year-workshops in 3 minutes and 47 seconds (queued for 2 seconds)
Name Stage Failure
build:latest Build
Entering 'assets/vendor/Font-Awesome'
HEAD is now at 4e6402443 Release 5.13.0 (#16353)
Entering 'assets/vendor/MathJax'
Entering 'assets/vendor/bootstrap'
HEAD is now at 548be2ed6 Offcanvas as component (#29017)
fatal: Needed a single revision
Unable to find current revision in submodule path 'assets/vendor/MathJax'
Cleaning up file based variables
ERROR: Job failed: exit code 1