chore: adjust title size

Author: yyx990803

README.md

@@ -14,13 +14,13 @@ yarn global add @vue/cli
 
 ## Usage
 
-#### Creating a New Project
+### Creating a New Project
 
 ``` sh
 vue create my-project
 ```
 
-#### Zero-config Prototyping
+### Zero-config Prototyping
 
 You can rapidly prototype with just a single `*.vue` file with the `vue serve` and `vue build` commands, but they require an additional global addon to be installed:
 
@@ -34,7 +34,7 @@ vue serve
 
 The drawback of `vue serve` is that it relies on globally installed dependencies which may be inconsistent on different machines. Therefore this is only recommended for rapid prototyping.
 
-#### Installing Plugins in an Existing Project
+### Installing Plugins in an Existing Project
 
 Each CLI plugin ships with a generator (which creates files) and a runtime plugin (which tweaks the core webpack config and injects commands). When you use `vue create` to create a new project, some plugins will be pre-installed for you based on your feature selection. In case you want to install a plugin into an already created project, simply install it first:
 
@@ -50,7 +50,7 @@ vue invoke eslint # the prefix can be omitted
 
 It is recommended to commit your project's current state before running `vue invoke`, so that after file generation you can review the changes and revert if needed.
 
-#### Pulling `[email protected]` Templates (Legacy)
+### Pulling `[email protected]` Templates (Legacy)
 
 `@vue/cli` uses the same `vue` binary, so it overwrites `[email protected]`. If you still need the legacy `vue init` functionality, you can install a global bridge:
 
@@ -60,7 +60,7 @@ yarn global add @vue/cli-init
 vue init webpack my-project
 ```
 
-#### Customization and Plugin Usage
+### Customization and Plugin Usage
 
 For a detailed guide on how to customize a project, recipes for common tasks, detailed usage for each plugin, please see the [full documentation](https://github.com/vuejs/vue-cli/blob/dev/docs/README.md).