release: sourcegraph@3.35.0

Created by: kevinwojo

This pull request is part of the Sourcegraph 3.35.0 release.

• Release batch change
• Tracking issue

Additional changes required

These steps must be completed before this PR can be merged, unless otherwise stated. Push any required changes directly to this PR branch.

• Update the upgrade guides in doc/admin/updates
• Ensure all other pull requests in the batch change have been merged - then run yarn run release release:finalize to generate the tags required, re-run Buildkite on this branch, and ensure the build passes before merging this pull request

cc @kevinwojo