Fix branch in installation guide

In the installation guide, the branch name is still master, but should be main. This MR fixes that.

added category: documentation label

assigned to @schueler

added 1 commit

• 32b7d5e2 - Fix branch in CONTRIBUTING

Compare with previous version

I just saw that the old branch name also still appears in the CONTRIBUTING.md, fixed that too.

approved this merge request

Thanks, for the fixes, I had overlooked these places..

merged

mentioned in commit 60af1eaf