add the ability to specify repository ref (#80)

closes #75

Reviewed-on: Plemya-x/ALR#80
Co-authored-by: Maxim Slipenko <no-reply@maxim.slipenko.com>
Co-committed-by: Maxim Slipenko <no-reply@maxim.slipenko.com>

pkg/repos/pull.go

@@ -391,17 +391,12 @@ func (rs *Repos) processRepoChanges(ctx context.Context, repo types.Repo, r *git
 			}
 			scriptFl, err := oldCommit.File(action.File)
 			if err != nil {
-				return fmt.Errorf("error getting file: %w", err)
+				return nil
 			}
 
 			r, err := scriptFl.Reader()
 			if err != nil {
-				return fmt.Errorf("error creating reader: %w", err)
-			}
-
-			runner, err := rs.processRepoChangesRunner(repoDir, filepath.Dir(filepath.Join(repoDir, action.File)))
-			if err != nil {
-				return fmt.Errorf("error creating process repo changes runner: %w", err)
+				return nil
 			}
 
 			var pkg db.Package