Remove replacement of plus with dot in python latest version (#10838)

* Remove replacement of + with .

* Remove feature flag

python/lib/dependabot/python/update_checker/latest_version_finder.rb

@@ -159,10 +159,7 @@ def filter_out_of_range_versions(versions_array)
         end
 
         def wants_prerelease?
-          if dependency.version
-            version = version_class.new(dependency.version.tr("+", "."))
-            return version.prerelease?
-          end
+          return version_class.new(dependency.version).prerelease? if dependency.version
 
           dependency.requirements.any? do |req|
             reqs = (req.fetch(:requirement) || "").split(",").map(&:strip)

python/spec/dependabot/python/update_checker/latest_version_finder_spec.rb

@@ -204,6 +204,12 @@
       end
 
       it { is_expected.to eq(Gem::Version.new("2.7.0b1")) }
+
+      context "with a local version" do
+        let(:dependency_version) { "2.6.0a1+local.1" }
+
+        it { is_expected.to eq(Gem::Version.new("2.7.0b1")) }
+      end
     end
 
     context "when raise_on_ignored is enabled and later versions are allowed" do