Fix semantic_version_spec.rb

This merge request fixes an issue with our specs that meant equality wasn't actually being checked. There are other specs in the project affected by this issue, which will be fixed over a few different merge requests. I came across this issue whilst refining Add valid? function to semver_dialects gem in order to check semantic versions.

Related Merge Request(s)

https://gitlab.com/gitlab-org/vulnerability-research/foss/semver_dialects/-/merge_requests/10+