fix: improve new-action-cache fetch failure error (#2172)

- include repoURL and repoRef in error
- map NoErrAlreadyUptodate to `couldn't find remote ref` for branchOrtag
  fetch request

Co-authored-by: mergify[bot] <37929162+mergify[bot]@users.noreply.github.com>

act/runner/action_cache.go

@@ -6,6 +6,7 @@ import (
 	"crypto/rand"
 	"encoding/hex"
 	"errors"
+	"fmt"
 	"io"
 	"io/fs"
 	"path"
@@ -86,6 +87,9 @@ func (c GoGitActionCache) Fetch(ctx context.Context, cacheDir, url, ref, token s
 		Auth:  auth,
 		Force: true,
 	}); err != nil {
+		if tagOrSha && errors.Is(err, git.NoErrAlreadyUpToDate) {
+			return "", fmt.Errorf("couldn't find remote ref \"%s\"", ref)
+		}
 		return "", err
 	}
 	if tagOrSha {