Update version to v7.4.0

nasa9084 · nasa9084 · commit 4e273f5a105e · 2020-05-11T14:13:05.000+09:00
diff --git a/linebot/version.go b/linebot/version.go
@@ -16,4 +16,4 @@
 
 package linebot
 
-const version = "7.3.0"
+const version = "7.4.0"
