feat(go/graph): add go code for graph_dfs/bfs (#372)

* feat(vertex): add a vertex pkg

* feat(graph): add graph_bfs in go

* feat(graph): add graph_dfs in go

* fix(graph): fix comment

* fix(graph): fix graph_adj_list

* fix(go/graph): fix graph_adjacency

* fix(c): gitignore

* feat(graph): print order adjList graph

* fix(graph): remove order print

* Update graph_adjacency_list_test.go

* Update .gitignore

* Update .gitignore

---------

Co-authored-by: Yudong Jin <krahets@163.com>

codes/go/chapter_graph/graph_dfs_test.go

@@ -0,0 +1,28 @@
+// File: graph_dfs_test.go
+// Created Time: 2023-02-18
+// Author: Reanon (793584285@qq.com)
+
+package chapter_graph
+
+import (
+	"fmt"
+	"testing"
+
+	. "github.com/krahets/hello-algo/pkg"
+)
+
+func TestGraphDFS(t *testing.T) {
+	/* 初始化无向图 */
+	vets := ValsToVets([]int{0, 1, 2, 3, 4, 5, 6})
+	edges := [][]Vertex{
+		{vets[0], vets[1]}, {vets[0], vets[3]}, {vets[1], vets[2]},
+		{vets[2], vets[5]}, {vets[4], vets[5]}, {vets[5], vets[6]}}
+	graph := newGraphAdjList(edges)
+	fmt.Println("初始化后，图为:")
+	graph.print()
+
+	/* 深度优先遍历 DFS */
+	res := graphDFS(graph, vets[0])
+	fmt.Println("深度优先遍历（DFS）顶点序列为:")
+	PrintSlice(VetsToVals(res))
+}