AngularJSで”ng serve"立ち上げ時のエラー解決

# エラー内容
Angular CLIでサーバーを立ち上げようとしたところ、
下記の様なエラーが出力され、日本語用の掲示板がなく、苦戦。

備忘録と日本語用の解決方法として記録する。

## 環境
* Mac OS Catalina 10.15.7
* zsh
* Node.js 15.0.1
* npm 7.0.3 
* Angular 10.0.14
* Angular CLI 10.0.8

## コード
立ち上げ

```zsh
% ng serve
```

すると下記の様なエラーが出力された。

```zsh
An unhandled exception occurred: Cannot find module '@angular-devkit/build-angular/package.json'
Require stack:
- /Users/username/.nodebrew/node/v15.0.1/lib/node_modules/@angular/cli/node_modules/@angular-devkit/architect/node/node-modules-architect-host.js
- /Users/username/.nodebrew/node/v15.0.1/lib/node_modules/@angular/cli/node_modules/@angular-devkit/architect/node/index.js
- /Users/username/.nodebrew/node/v15.0.1/lib/node_modules/@angular/cli/models/architect-command.js
- /Users/username/.nodebrew/node/v15.0.1/lib/node_modules/@angular/cli/commands/serve-impl.js
- /Users/username/.nodebrew/node/v15.0.1/lib/node_modules/@angular/cli/node_modules/@angular-devkit/schematics/tools/export-ref.js
- /Users/username/.nodebrew/node/v15.0.1/lib/node_modules/@angular/cli/node_modules/@angular-devkit/schematics/tools/index.js
- /Users/username/.nodebrew/node/v15.0.1/lib/node_modules/@angular/cli/utilities/json-schema.js
- /Users/username/.nodebrew/node/v15.0.1/lib/node_modules/@angular/cli/models/command-runner.js
- /Users/username/.nodebrew/node/v15.0.1/lib/node_modules/@angular/cli/lib/cli/index.js
- /Users/username/.nodebrew/node/v15.0.1/lib/node_modules/@angular/cli/lib/init.js
- /Users/username/.nodebrew/node/v15.0.1/lib/node_modules/@angular/cli/bin/ng
See "/private/var/folders/mz/z5f4vq_n6vz50y0g7vt85v4r0000gn/T/ng-7crVaj/angular-errors.log" for further details.
```
エラーの解決方法がググって検察してみたものの
なかなか出てこず、うまくいかず下記のサイトにてようやく答えが見つかる。
参考：[Cannot find module @angular-devkit/build-angular/package.json](https://www.thecodebuzz.com/cannot-find-module-angular-devkit-build-angular-package-json/)

```zsh
% npm install --save-dev @angular-devkit/build-angular
```
と入力したら

```
added 1484 packages, and audited 1484 packages in 21s

4 high severity vulnerabilities

To address all issues (including breaking changes), run:
  npm audit fix --force

Run `npm audit` for details.
```

と出力されたので、指示通り、

```zsh
% npm audit fix --force
```
と入力。

改めて

```zsh
% ng serve
```
を入力したところ、

```zsh
Your global Angular CLI version (10.2.0) is greater than your local
version (10.0.8). The local Angular CLI version is used.

To disable this warning use "ng config -g cli.warnings.versionMismatch false".
Compiling @angular/core : es2015 as esm2015
Compiling @angular/animations : es2015 as esm2015
Compiling @angular/cdk/keycodes : es2015 as esm2015
Compiling @angular/common : es2015 as esm2015
Compiling @angular/cdk/observers : es2015 as esm2015
Compiling @angular/animations/browser : es2015 as esm2015
Compiling @angular/platform-browser : es2015 as esm2015
Compiling @angular/cdk/platform : es2015 as esm2015
Compiling @angular/cdk/bidi : es2015 as esm2015
Compiling @angular/forms : es2015 as esm2015
Compiling @angular/router : es2015 as esm2015
Compiling @angular/platform-browser-dynamic : es2015 as esm2015
Compiling @angular/platform-browser/animations : es2015 as esm2015
Compiling @angular/cdk/a11y : es2015 as esm2015
Compiling @angular/material/core : es2015 as esm2015
Compiling @angular/material/button : es2015 as esm2015
Compiling @angular/material/toolbar : es2015 as esm2015

chunk {main} main.js, main.js.map (main) 19.7 kB [initial] [rendered]
chunk {polyfills} polyfills.js, polyfills.js.map (polyfills) 141 kB [initial] [rendered]
chunk {runtime} runtime.js, runtime.js.map (runtime) 6.15 kB [entry] [rendered]
chunk {styles} styles.js, styles.js.map (styles) 168 kB [initial] [rendered]
chunk {vendor} vendor.js, vendor.js.map (vendor) 3.2 MB [initial] [rendered]
Date: 2020-10-25T02:26:54.690Z - Hash: 3772bde64fed4e4284bc - Time: 5678ms
** Angular Live Development Server is listening on localhost:4200, open your browser on http://localhost:4200/ **
: Compiled successfully.
```

無事立ち上がった！

ps　エラー解決には英語も欠かせないな