Update version to v6.0.0

sugyan · sugyan · commit 3f6c2b7deef9 · 2019-03-14T18:49:13.000+09:00
diff --git a/linebot/version.go b/linebot/version.go
@@ -16,4 +16,4 @@
 
 package linebot
 
-const version = "5.0.0"
+const version = "6.0.0"
