chore: ci: set bootstrap-sha for release-please base

[BethGriggs]

Fixing teething issues found in #1144.

Checklist

• npm test passes
• contribution guidelines followed
  here

[codecov-commenter]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 96.20%. Comparing base (dd6deee) to head (2a71918).

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #1145   +/-   ##
=======================================
  Coverage   96.20%   96.20%           
=======================================
  Files          29       29           
  Lines        2213     2213           
=======================================
  Hits         2129     2129           
  Misses         84       84           

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[BethGriggs]

Going to merge this quicker than usual to debug the new release process