WIP: Use gitlab API to get the latest version

[debasishbsws]

For this code to work it needs chainguard-dev/melange#1231 code changes in melange.

To tryout locally

1. Clone the melange repository locally and checkout to Add GitLabMonitor update configuration chainguard-dev/melange#1231
2. use replace chainguard.dev/melange => ../your-local-melange-clone-path in the end of your wolfictl go.mod file and run go mod tidy

It should now use the local melange copy to build.

How it works:

for packages that are using gitlab projects we can use it to get the latest version ant its corresponding commit. for example in gitlab-pages package modify the update block with

update:
  enabled: true
  gitlab:
    identifier: gitlab-org/gitlab-pages
    strip-prefix: v
    use-tag: true

And now we can run ../wolfictl check update gitlab-pages.yaml or any other command.

NOTE: Need a GitLab token without any permission, set it in your env var export GITLAB_TOKEN=your-gitlab-token