add Go

Author: zhaoguanchen

Golang/go.mod

@@ -0,0 +1,3 @@
+module Golang
+
+go 1.19

Golang/solution/binarytree/PathSum.go

@@ -0,0 +1,5 @@
+package binarytree
+
+func main() {
+
+}

Golang/structure/structure.go

@@ -0,0 +1,12 @@
+package structure
+
+type ListNode struct {
+	val  int
+	next *ListNode
+}
+
+type TreeNode struct {
+	val   int
+	left  *TreeNode
+	right *TreeNode
+}