3.26 release tracking issue

Created by: davejrt

3.26 release

This release is scheduled for Mar 20, 2021, 6:00 PM (UTC).

Setup

Ensure release configuration in dev/release/release-config.jsonc on main is up to date with the parameters for the current release.
Ensure you have the latest version of the release tooling and configuration by checking out and updating sourcegraph@main.

Prepare release

Post a release status update to Slack - review all release-blocking issues, and ensure someone is resolving each.
```
yarn release release:status
```

Do the branch cut for the release:

Update the changelog and merge the generated pull request:
```
yarn release changelog:cut
```
Create the 3.26 branch off the CHANGELOG commit in the previous step:
```
git branch 3.26 && git push origin 3.26
```

Upon branch cut, create and test release candidates:

Tag the first release candidate:

N=1 yarn release release:create-candidate $N

Wait for the Sourcegraph pipeline, QA pipeline, and E2E pipeline in Buildkite to complete.
File any failures and regressions in the pipelines as release-blocker issues and assign the appropriate teams.

Revert or disable features that may cause delays. As necessary, git cherry-pick bugfix (not feature!) commits from main into the release branch. Continue to create new release candidates as necessary, until no more release-blocker issues remain.

Post a release status update to Slack:
```
yarn release release:status
```

Stage release

Once there are no more release-blocking issues (as reported by the release:status command) proceed with creating the final release:

Verify the CHANGELOG on main and 3.26 are accurate.

Tag the final release:

yarn release release:create-candidate final

Ensure the Sourcegraph pipeline, QA pipeline, and E2E pipeline in Buildkite passes, and for the release Docker images to be available in Docker Hub.
Open PRs that publish the new release and address any action items required to finalize draft PRs (track PR status via the generated release campaign):
```
yarn release release:stage
```

Finalize release

From the release campaign, merge the release-publishing PRs created previously.
- For deploy-sourcegraph, also:
  - Tag the v3.26.0 release at the most recent commit on the v3.26 branch.
```
VERSION='v3.26.0' bash -c 'git tag -a "$VERSION" -m "$VERSION" && git push origin "$VERSION"'
```
- For sourcegraph, also:
  - Cherry pick the release-publishing PR from sourcegraph/sourcegraph@main into the release branch.
Ask the product team (#product) to merge the blog post. Add the pull request to the release campaign:
```
yarn release release:add-to-campaign sourcegraph/about <pr-number>
```
Finalize and announce that the release is live:
```
yarn release release:close
```

Post-release

Notify the next release captain that they are on duty for the next release. They should complete the steps in this section.

Open a PR to update dev/release/release-config.jsonc with the parameters for the current release.
Ensure you have the latest version of the release tooling and configuration by checking out and updating sourcegraph@main.
Create release calendar events, tracking issue, and announcement for next release:
```
yarn run release tracking:issues
yarn run release tracking:timeline
```
Close this issue.

Note: If a patch release is requested after the release, ask that a patch request issue be filled out and approved first.