[infra] Add go/skia-break-glass to gardener documentation

Bug: skia:12124
Change-Id: I8821e091b4ec823eaa7cff6c3426c13a31b6f362
No-Try: true
Docs-Preview: https://skia.org/?cl=444776
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/444776
Reviewed-by: Ravi Mistry <rmistry@google.com>
1 file changed