Ignore certain buildbots

[hugovk]

During the 3.14.6 release:

The following buildbots are failing:
- wasm32-wasi Non-Debug 3.14

Check https://buildbot.python.org/all/#/release_status for more information

Do you want to continue even if these builders are failing?
Enter yes or no: yes

This is caused by some bad buildbot config, quickly fixed, but the builds are now part of history:

https://buildbot.python.org/all/#/builders/1918

A couple of options to fix in release-tools:

• Ignore that specific builder
• Ignore any builders that haven't run in N days

[zware]

• Ignore any builders that haven't run in N days

I'd suggest this one. Something in the 7-14 day range seems like a reasonable cutoff for this to me.

[hugovk]

PR #415 adds a 14 day cutoff.