docs: update contribution guide (#9668)

.github/CONTRIBUTING.md

@@ -29,9 +29,5 @@ It's welcomed to pull request, And there are some tips about that:
 ```bash
 git clone git@github.com:youzan/vant.git
 
-cd packages/vant && yarn
+yarn && yarn dev
-
-npm run dev
-
-# open http://localhost:8080
 ```

packages/vant-popperjs/tsconfig.json

@@ -1,6 +1,6 @@
 {
   "compilerOptions": {
-    "target": "ES5",
+    "target": "ES2015",
     "outDir": "./dist",
     "module": "ES2015",
     "strict": true,

packages/vant-use/tsconfig.json

@@ -1,6 +1,6 @@
 {
   "compilerOptions": {
-    "target": "ES5",
+    "target": "ES2015",
     "outDir": "./dist/types",
     "module": "ES2015",
     "strict": true,

packages/vant/docs/markdown/contribution.zh-CN.md

@@ -19,15 +19,15 @@
 
 ```bash
 # 克隆仓库
-# 默认为 dev 分支，包含 Vant 3 的代码
+# 默认为 dev 分支，对应 Vant 3 的代码
 # 如果需要在 Vant 2 上进行更改，请基于 2.x 分支进行开发
 git clone git@github.com:youzan/vant.git
 
 # 安装依赖
-cd vant && yarn
+yarn
 
-# 进入开发模式，浏览器访问 http://localhost:8080
+# 进入开发模式，浏览器访问 localhost
-npm run dev
+yarn dev
 ```
 
 ### 目录结构

packages/vant/tsconfig.json

@@ -2,14 +2,14 @@
   "compilerOptions": {
     "baseUrl": ".",
     "jsx": "preserve",
-    "target": "ES2019",
+    "target": "ES2015",
-    "module": "ESNext",
+    "module": "ES2015",
     "strict": true,
     "allowJs": true,
     "skipLibCheck": true,
     "noImplicitThis": true,
     "esModuleInterop": true,
-    "moduleResolution": "node",
+    "moduleResolution": "node"
   },
   "include": ["src/**/*", "types/**/*", "docs/**/*", "test/**/*"]
 }