Update activesupport requirement from >= 4.2, < 8 to >= 4.2, < 9

Updates the requirements on [activesupport](https://github.com/rails/rails) to permit the latest version.
- [Release notes](https://github.com/rails/rails/releases)
- [Changelog](https://github.com/rails/rails/blob/v8.0.0/activesupport/CHANGELOG.md)
- [Commits](rails/rails@v4.2.0...v7.2.2)

---
updated-dependencies:
- dependency-name: activesupport
  dependency-type: direct:production
...

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

gemstash.gemspec

@@ -31,7 +31,7 @@ you push your own private gems as well."
 
   spec.required_ruby_version = ">= 3.1"
 
-  spec.add_runtime_dependency "activesupport", ">= 4.2", "< 8"
+  spec.add_runtime_dependency "activesupport", ">= 4.2", "< 9"
   spec.add_runtime_dependency "dalli", ">= 3.2.3", "< 4"
   spec.add_runtime_dependency "faraday", ">= 1", "< 3"
   spec.add_runtime_dependency "faraday_middleware", "~> 1.0"