Creating github releases from non-master

[kcpevey]

Due to github's change from naming the base branch main instead of master, I had to update these lines to get my github release action to work since it assumed that I was releasing from master.

However, I would also contend that its possible to release from any branch, which would suggest that this option should be exposed to users.

[scopatz]

Thanks for reporting @kcpevey! Potential fix in #238 if you want to try it out

[kcpevey]

I'll give it a try!

[scopatz]

Great thanks!

[kcpevey]

Works great for me! Thank you so much!