fix(@angular-devkit/build-angular): add karma as an optional peer dependency

karma is currently used by the karma builder within this package but is not represented in the dependencies.  The can lead to accidental version mismatches as well as package manager hoisting problems due to the package manager not knowing the full dependency set of the package.

Author: clydin

packages/angular_devkit/build_angular/package.json

@@ -81,13 +81,17 @@
   "peerDependencies": {
     "@angular/compiler-cli": "^11.0.0 || ^11.0.0-next",
     "@angular/localize": "^11.0.0 || ^11.0.0-next",
+    "karma": "^5.2.0",
     "ng-packagr": "^10.0.0",
     "typescript": ">=3.9 < 4.1"
   },
   "peerDependenciesMeta": {
     "@angular/localize": {
       "optional": true
     },
+    "karma": {
+      "optional": true
+    },
     "ng-packagr": {
       "optional": true
     }

packages/angular_devkit/build_angular/src/karma/index.ts

@@ -26,7 +26,6 @@ import { SingleTestTransformLoader } from '../webpack/plugins/single-test-transf
 import { findTests } from './find-tests';
 import { Schema as KarmaBuilderOptions } from './schema';
 
-// tslint:disable-next-line:no-implicit-dependencies
 export type KarmaConfigOptions = import('karma').ConfigOptions & {
   buildWebpack?: unknown;
   configFile?: string;
@@ -36,7 +35,6 @@ async function initialize(
   options: KarmaBuilderOptions,
   context: BuilderContext,
   webpackConfigurationTransformer?: ExecutionTransformer<webpack.Configuration>,
-  // tslint:disable-next-line:no-implicit-dependencies
 ): Promise<[typeof import('karma'), webpack.Configuration]> {
   const { config } = await generateBrowserWebpackConfigFromContext(
     // only two properties are missing:
@@ -53,7 +51,6 @@ async function initialize(
     ],
   );
 
-  // tslint:disable-next-line:no-implicit-dependencies
   const karma = await import('karma');
 
   return [