Fix non-existing branch error in section "Subversion to Git Transition"

[mfasold]

In the subsection "Create a new GitHub repository for an existing Bioconductor package" within "Subversion to Git Transition" of the git version control page, there is a problem in steps 8 /9 of the guide.

The user clones an empty repo from GitHub. He will start in the branch main. In step 8, the aim is to merge upstreams devel branch with origins devel branch, and push those changes in step 9. As the user is in the main branch, those changes will be merged to main. And in step 9 there appears an error, as the devel branch does not exist. So one has to create and checkout a new devel branch in origin first.

[lshep]

Would it be better however to just rename the default branch on github to devel so that they match and make it easier to push / pull to the same named branch instead of then having to do things like git push upstream main:devel or git pull upstream devel:main . It ERROR but the commands to fix it this main:devel are in the section right above that. We made a blog about it -- https://blog.bioconductor.org/posts/2023-03-01-transition-to-devel/ -- maybe having/mentioning both options renaming and just checking out a new branch.

[LiNk-NY]

@mfasold
I think we should add a note for those that don't use devel as the default branch:
git branch -M devel
rather than checking out the devel branch

[LiNk-NY]

It should probably be a note rather than recommending the user checkout the devel branch. We want to encourage that organizations use a devel branch as the default but also give the option to change the name of the branch if it is not the case.

[LiNk-NY]

Instead of this, add a note below it saying something like if the default branch is not devel use:

git branch -M devel