Maintenance: Bump bootsnap from 1.9.0 to 1.9.1

Bumps [bootsnap](https://github.com/Shopify/bootsnap) from 1.9.0 to 1.9.1.
- [Release notes](https://github.com/Shopify/bootsnap/releases)
- [Changelog](https://github.com/Shopify/bootsnap/blob/master/CHANGELOG.md)
- [Commits](https://github.com/Shopify/bootsnap/compare/v1.9.0...v1.9.1)

Gemfile.lock

@@ -119,7 +119,7 @@ GEM
     biz (1.8.2)
       clavius (~> 1.0)
       tzinfo
-    bootsnap (1.9.0)
+    bootsnap (1.9.1)
       msgpack (~> 1.0)
     brakeman (5.1.1)
     browser (5.3.1)