Bump rubocop-ast from 1.31.0 to 1.31.1 (#517)

Bumps [rubocop-ast](https://github.com/rubocop/rubocop-ast) from 1.31.0 to 1.31.1.
- [Release notes](https://github.com/rubocop/rubocop-ast/releases)
- [Changelog](https://github.com/rubocop/rubocop-ast/blob/master/CHANGELOG.md)
- [Commits](rubocop/rubocop-ast@v1.31.0...v1.31.1)

---
updated-dependencies:
- dependency-name: rubocop-ast
  dependency-type: indirect
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <[email protected]>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Gemfile.lock

@@ -38,7 +38,6 @@ GEM
       ruby-rc4
       ttfunk
     pkg-config (1.5.6)
-    prism (0.24.0)
     racc (1.7.3)
     rainbow (3.1.1)
     rake (13.1.0)
@@ -71,9 +70,8 @@ GEM
       rubocop-ast (>= 1.30.0, < 2.0)
       ruby-progressbar (~> 1.7)
       unicode-display_width (>= 2.4.0, < 3.0)
-    rubocop-ast (1.31.0)
+    rubocop-ast (1.31.1)
       parser (>= 3.3.0.4)
-      prism (>= 0.24.0)
     rubocop-capybara (2.20.0)
       rubocop (~> 1.41)
     rubocop-factory_bot (2.25.1)