Update prometheus-client requirement from ~> 2.0 to >= 2, < 5

Updates the requirements on [prometheus-client](https://github.com/prometheus/client_ruby) to permit the latest version.
- [Release notes](https://github.com/prometheus/client_ruby/releases)
- [Changelog](https://github.com/prometheus/client_ruby/blob/main/CHANGELOG.md)
- [Commits](https://github.com/prometheus/client_ruby/compare/v2.1.0...v4.1.0)

---
updated-dependencies:
- dependency-name: prometheus-client
  dependency-type: direct:production
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <support@github.com>

Gemfile.lock

@@ -14,7 +14,7 @@ PATH
       opentelemetry-resource_detectors (= 0.23.0)
       opentelemetry-sdk (~> 1.0, >= 1.0.2)
       pickup (~> 0.0.11)
-      prometheus-client (~> 2.0)
+      prometheus-client (>= 2, < 5)
       puma (~> 5.0, >= 5.0.4)
       rack (>= 2.2, < 4.0)
       rake (~> 13.0)
@@ -93,7 +93,7 @@ GEM
     parser (3.2.1.0)
       ast (~> 2.4.1)
     pickup (0.0.11)
-    prometheus-client (2.1.0)
+    prometheus-client (4.1.0)
     pry (0.14.2)
       coderay (~> 1.1)
       method_source (~> 1.0)

vmpooler.gemspec

@@ -28,7 +28,7 @@ Gem::Specification.new do |s|
   s.add_dependency 'opentelemetry-resource_detectors', '= 0.23.0'
   s.add_dependency 'opentelemetry-sdk', '~> 1.0', '>= 1.0.2'
   s.add_dependency 'pickup', '~> 0.0.11'
-  s.add_dependency 'prometheus-client', '~> 2.0'
+  s.add_dependency 'prometheus-client', '>= 2', '< 5'
   s.add_dependency 'puma', '~> 5.0', '>= 5.0.4'
   s.add_dependency 'rack', '>= 2.2', '< 4.0'
   s.add_dependency 'rake', '~> 13.0'