final updates for next v12.1.0 release

[jbathegit]

Fixes #586

@AlexanderRichert-NOAA @edwardhartnett As noted in some other threads, I'm still unsure about how (or whether?) to update the spack/package.py file to add a new entry for this new release. Or is that something that needs to be done post-release? I know the sha256 values in spack/package.py are different from the commit ids which correspond to the github tags for each release, but again I'm unsure about how or when to make that corresponding update to the file. Please let me know ASAP, or else I guess I'll just go ahead and do the next release after this PR is merged and with what we have for now.

[jbathegit]

@AlexanderRichert-NOAA @edwardhartnett As noted in some other threads, I'm still unsure about how (or whether?) to update the spack/package.py file to add a new entry for this new release. Or is that something that needs to be done post-release? I know the sha256 values in spack/package.py are different from the commit ids which correspond to the github tags for each release, but again I'm unsure about how or when to make that corresponding update to the file. Please let me know ASAP, or else I guess I'll just go ahead and do the next release after this PR is merged and with what we have for now.

Never mind, I eventually found the answer to this myself in #552 and made the corresponding update in #609

[edwardhartnett]

I do the spack files after the release.

[jbathegit]

I do the spack files after the release.

@edwardhartnett as noted above, and since I'd never gotten a reply back, I did some further digging on my own and found (what I thought was?) the answer in #552. And with that information I correspondingly went ahead and submitted a new PR #609 after the v12.1.0 release.

Please take a look at the changes I made in #609, and if I missed anything then please feel free to submit your own commit on top of mine within that same PR, and we can just merge any needed changes from there.