Allow commit SHAs when building CAPI components

Our release process expects CAPI infrastructure providers to use a semantic version in the [`GIT_TAG`](https://github.com/aws/eks-anywhere-build-tooling/blob/main/projects/kubernetes-sigs/cluster-api-provider-cloudstack/GIT_TAG) file. While semantic versions are more useful for comparisons than commit SHAs, it can be necessary to use a commit SHA for the build (perhaps a tag isn't available and won't be for some time).

This feature request is to support using commit SHAs when building CAPI components (specifically infrastructure providers).

Start with the linked GIT_TAG file for the example CAPI infrastructure provider and trace the release build logic that requires a semantic version. Identify where the tag format is validated or consumed, then verify that a commit SHA can be used to build the provider without breaking the existing semantic-version path.

Written by the indexing model from the issue text.