Do not indent blank lines

The test case contains blank lines with white-spaces
and many editors do trim those, so we adopt the test
as well as the code to not indent blank lines

Author: fwiesel

diff/diff.go

@@ -210,7 +210,11 @@ func printDiffRecord(diff difflib.DiffRecord, to io.Writer) {
 	case difflib.LeftOnly:
 		fmt.Fprintf(to, "%s\n", ansi.Color("- "+text, "red"))
 	case difflib.Common:
-		fmt.Fprintf(to, "%s\n", "  "+text)
+		if text == "" {
+			fmt.Fprintln(to)
+		} else {
+			fmt.Fprintf(to, "%s\n", "  "+text)
+		}
 	}
 }
 

diff/diff_test.go

@@ -204,13 +204,13 @@ metadata:
 		}
 
 		require.Equal(t, `default, nginx, Deployment (apps) has changed:
-  
+
 - apiVersion: apps/v1beta1
 + apiVersion: apps/v1
   kind: Deployment
   metadata:
     name: nginx
-  
+
 `, buf1.String())
 	})