Fix GoGitClient to support tags in branch field

[Copilot]

Users reported "Reference not found" errors when specifying tags in the branch field after upgrading to the Go git client. The issue occurs because GoGitClient.Clone() hardcodes plumbing.NewBranchReferenceName(), which expects refs/heads/* but tags use refs/tags/*.

Changes

• Added resolveReferenceName() method - Lists remote references to determine if the provided name is a branch or tag, returns appropriate plumbing.ReferenceName
• Modified Clone() to use resolved reference - Calls resolveReferenceName() before cloning, falls back to branch assumption if resolution fails
• Added unit tests - Verify reference resolution logic and plumbing reference name creation

// Before: hardcoded branch reference
ReferenceName: plumbing.NewBranchReferenceName(r.Repository.GitBranch),

// After: resolve branch or tag
refName, refErr := c.resolveReferenceName(r)
if refErr != nil {
    r.Logger.Log("Warning: Unable to resolve reference type, assuming branch: " + refErr.Error())
    refName = plumbing.NewBranchReferenceName(r.Repository.GitBranch)
}
ReferenceName: refName,

This aligns GoGitClient behavior with CmdGitClient, where git clone --branch already accepts both branches and tags.

Original prompt

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This section details on the original issue you should resolve

<issue_title>Cannot use tag for repo with the new go git client</issue_title>
<issue_description>Hello,

Thank you for this fantastic tool!

I just updated from v2.8.80 to v2.8.89. Previously I was able to set a tag in the branch field when I added a new repo with the new go git client I got an error message with the following: Reference not found.

I am using Semaphore from the Docker environment. Is it possible to use an external git client by specifying an environment variable?</issue_description>

Comments on the Issue (you are @copilot in this section)

@fiftin Yes, will do @fiftin Please check version 2.8.90.

• Fixes Cannot use tag for repo with the new go git client #1220

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