Update go.mod

Yuan Ting · web-flow · commit 438167e31f36 · 2019-11-01T15:42:52.000+08:00
diff --git a/go.mod b/go.mod
@@ -1,3 +1,3 @@
 module github.com/timmyyuan/go-gitdiff
 
-go 1.12
+go 1.13

Original file line number	Diff line number	Diff line change
`@@ -1,3 +1,3 @@`
`1`	`1`	`module github.com/timmyyuan/go-gitdiff`
`2`	`2`
`3`		`-go 1.12`
	`3`	`+go 1.13`