fix: return error on reusable workflows (#1093)

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

act/model/workflow.go

@@ -84,6 +84,7 @@ type Job struct {
 	RawContainer   yaml.Node                 `yaml:"container"`
 	Defaults       Defaults                  `yaml:"defaults"`
 	Outputs        map[string]string         `yaml:"outputs"`
+	Uses           string                    `yaml:"uses"`
 	Result         string
 }