op-deployer: Marshal tag-based ArtifactsLocator with correct scheme (#12494)

op-deployer/pkg/deployer/opcm/artifacts_locator.go

@@ -45,7 +45,7 @@ func (a *ArtifactsLocator) MarshalText() ([]byte, error) {
 	}
 
 	if a.Tag != "" {
-		return []byte(a.Tag), nil
+		return []byte("tag://" + a.Tag), nil
 	}
 
 	return nil, fmt.Errorf("no URL, path or tag set")

op-deployer/pkg/deployer/opcm/artifacts_locator_test.go

@@ -79,6 +79,10 @@ func TestArtifactsLocator_Marshaling(t *testing.T) {
 			}
 			require.NoError(t, err)
 			require.Equal(t, tt.out, &a)
+
+			marshalled, err := a.MarshalText()
+			require.NoError(t, err)
+			require.Equal(t, tt.in, string(marshalled))
 		})
 	}
 }