binary size: Add supersize reports for M77.

Change-Id: Iecab9924c9035887e946ffa994fcb757b00d054e
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1731785
Auto-Submit: Eric Stevenson <estevenson@chromium.org>
Reviewed-by: Samuel Huang <huangs@chromium.org>
Commit-Queue: Samuel Huang <huangs@chromium.org>
Cr-Commit-Position: refs/heads/master@{#683464}

tools/binary_size/generate_milestone_reports.py

@@ -67,6 +67,7 @@ _DESIRED_VERSIONS = [
     '74.0.3729.112',
     '75.0.3770.143',
     '76.0.3809.62',
+    '77.0.3861.0',  # Canary
 ]