storage: 26.2 branch checklist

[jbowens]

Checklist for things that need to be done when a release branch is cut (And always refer to wiki for latest instructions https://cockroachlabs.atlassian.net/wiki/spaces/STOR/pages/4672553027/Pebble+Releases)

• [Pebble repo] Cut crl-release-xy.z branch in Pebble at the same SHA that the release-xy.z branch is using
• [Pebble repo] Add crl-release-xy.z to the nightly workflow (in Pebble actions).
  • Copy the last release-ab.c.yaml file to release-xy.z.yaml
  • Update title and BRANCH
  • Update the go_version fields if necessary (they should match the Go that is used on the CRDB branch)
• [Pebble repo] Update Makefile to specify the previous version
  • Example PR: Makefile: set crl-release-25.2 as previous version and update crossversion target pebble#5008
• [CRDB repo] Update bump-pebble.sh and teamcity scripts on branch release-xy.z to use crl-release-xy.z instead of master
  • Example PR: release-25.2: teamcity, scripts: switch to release branches in Pebble scripts #144185
• [TeamCity] Update the crossversion meta config to include crl-release-xy.z https://teamcity.cockroachdb.com/admin/editBuildRunners.html?id=buildType:Cockroach_Nightlies_NightlyPebbleMetamorphicCrossversion
• [CRDB repo] Clone this issue for the next release
  • ticket for next release: TODO

Jira issue: CRDB-57835