Merge pull request #604 from alphagov/dependabot/bundler/bootsnap-1.21.0

Author: govuk-ci

Gemfile.lock

@@ -39,7 +39,7 @@ GEM
     base64 (0.3.0)
     benchmark (0.5.0)
     bigdecimal (3.3.1)
-    bootsnap (1.20.1)
+    bootsnap (1.21.0)
       msgpack (~> 1.2)
     brakeman (7.1.2)
       racc