Deploy 66ad8b51 to production

[stephenmcgruer]

Previous deployment was #2438 (ec7c97f)

Changelist ec7c97f...66ad8b5

This is a sizeable update. Major changes:

• Add compat2021 dashboard ([compat2021] Add an initial /compat2021 page #2443, [compat2021] Add summary scores component #2470, [compat2021] Add chart component #2471, [compat2021] Add stable checkbox and update URL as feature/stable change #2472, [compat2021] Link to the compat2021 page from the site header #2478)
• [triage] Add support for searching for test-level triage [triage] Add support for searching for test-level triage #2440
• [triage] Add a 'file issue' link for test-level issues [triage] Add a 'file issue' link for test-level issues #2439
• Remove deprecated experimentalByDefault and experimentalAligned flags Remove deprecated experimentalByDefault and experimentalAligned flags #2449
• Remove never-launched /api/prs endpoint and related frontend code Remove never-launched /api/prs endpoint and related frontend code #2466
• Remove deprecated useReftestAnalyzer flag Remove deprecated useReftestAnalyzer flag #2467
• Remove deprecated interopScoreColumn flag Remove deprecated interopScoreColumn flag #2468
• Remove obsolete 'experimentalAlignedExceptEdge' admin flag Remove obsolete 'experimentalAlignedExceptEdge' admin flag #2433
• Upgrade major version of taskcluster Upgrade major version of taskcluster #2441

This push is happening as part of the regular weekly push.

Pushing all three services - webapp, processor, and searchcache.

[stephenmcgruer]

We need a go mod update first. The new SHA to be deployed will be whatever #2480 becomes when it lands

[stephenmcgruer]

New SHA is 66ad8b5

[stephenmcgruer]

All services deployed, and promoted to 100% of traffic.