Initiate PRs on rel/* branches

[effigies]

Over at nipy/nipype, we use rel/X.Y.Z branches to update version numbers and perform any last-minute testing (to catch such things as deprecations or other issues that might hide until the version number is bumped). One of the tests we run is to make sure that our conda packages build correctly (see conda-forge/nipype-feedstock#12), which evolves on release into a PR identical to the one your bot submits (conda-forge/nipype-feedstock#13).

Basically, in order to make your bot non-redundant for our purposes, it would be nice to watch for rel/* branches and create/update the PR as it progresses. I don't know how plausible that is, given your architecture, but I've been thinking of doing something similar in our own CI scripts, and it seems that if you're providing this service, it might make more sense to try to augment your effort than initiate our own.

To be really explicit about the logic:

• On initial rel/* branch creation, create a *-feedstock PR that pins to the latest commit in the branch (example title: "nipype rel/1.0.2")
• On each push update commit and sha256sum
• On tag x.y.z, check for existing rel/x.y.z PR, update to pin to tag and final sha256sum

Some form of rate-limiting might be reasonable, such as requiring a string in the commit message (e.g. [release candidate]), or triggering only after completed CI.

Does this seem like an idea worth pursuing?

[CJ-Wright]

Might I suggest rever? Rever forms part of the backbone for the bot. When you tag rever will put in a PR into the feedstock.

We are planning on working on not PRing when there is a PR existing for that version of the package.