Build(deps): Bump rubocop-ast from 1.30.0 to 1.31.0 in /spec

Bumps [rubocop-ast](https://github.com/rubocop/rubocop-ast) from 1.30.0 to 1.31.0.
- [Release notes](https://github.com/rubocop/rubocop-ast/releases)
- [Changelog](https://github.com/rubocop/rubocop-ast/blob/master/CHANGELOG.md)
- [Commits](rubocop/rubocop-ast@v1.30.0...v1.31.0)

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

Signed-off-by: dependabot[bot] <[email protected]>

spec/Gemfile.lock

@@ -11,6 +11,7 @@ GEM
     parser (3.3.0.5)
       ast (~> 2.4.1)
       racc
+    prism (0.24.0)
     racc (1.7.3)
     rainbow (3.1.1)
     regexp_parser (2.9.0)
@@ -39,8 +40,9 @@ GEM
       rubocop-ast (>= 1.30.0, < 2.0)
       ruby-progressbar (~> 1.7)
       unicode-display_width (>= 2.4.0, < 3.0)
-    rubocop-ast (1.30.0)
-      parser (>= 3.2.1.0)
+    rubocop-ast (1.31.0)
+      parser (>= 3.3.0.4)
+      prism (>= 0.24.0)
     ruby-progressbar (1.13.0)
     semi_semantic (1.2.0)
     unicode-display_width (2.5.0)