feat: turn favicons into a peer dependency

BREAKING CHANGE: favicons needs to be installed separately

README.md

@@ -6,9 +6,9 @@ Leverages on [favicons](https://github.com/haydenbleasel/favicons) to automatica
 
 ## Installation
 
-Install the plugin with npm:
+Install the plugin and [favicons](https://github.com/haydenbleasel/favicons) with npm:
 ```shell
-$ npm install --save-dev favicons-webpack-plugin
+$ npm install --save-dev favicons favicons-webpack-plugin
 ```
 
 ## Zero Config Usage

package.json

@@ -50,6 +50,7 @@
     "cz-conventional-changelog": "3.0.2",
     "diffable-html": "4.0.0",
     "eslint": "^6.8.0",
+    "favicons": "^6.2.0",
     "fs-extra": "^8.1.0",
     "html-webpack-plugin": "^5.0.0-alpha.7",
     "image-size": "0.8.3",
@@ -66,7 +67,6 @@
     "@types/favicons": "5.5.0",
     "cache-loader": "^4.1.0",
     "camelcase": "^5.3.1",
-    "favicons": "^6.2.0",
     "find-cache-dir": "^3.2.0",
     "find-root": "^1.1.0",
     "loader-utils": "^1.2.3",
@@ -76,6 +76,7 @@
   },
   "peerDependencies": {
     "webpack": "^5.0.0"
+    "favicons": ">= 6.2.0"
   },
   "optionalDependencies": {
     "html-webpack-plugin": ">=5.0.0 || ^5.0.0-alpha.7"