fix: don't clobber recipe changes during `generate`

Closes #255

cli/catalogue/generate.go

@@ -134,6 +134,15 @@ A new catalogue copy can be published to the recipes repository by passing the
 					logrus.Fatal(err)
 				}
 
+				isClean, err := gitPkg.IsClean(rm.Name)
+				if err != nil {
+					return
+				}
+
+				if !isClean {
+					logrus.Fatalf("'%s' has locally unstaged changes", rm.Name)
+				}
+
 				if err := gitPkg.EnsureUpToDate(recipeDir); err != nil {
 					logrus.Fatal(err)
 				}