Add supports-color as optional peerDependency

This is the proper way to declare this type of dependency.

Note that if `peerDependenciesMeta` is not supported by the package
manager and `supports-color` is not installed, a warning will be
displayed.

Author: jgierer12

package.json

@@ -47,5 +47,13 @@
     "xo": "^0.23.0"
   },
   "main": "./src/index.js",
-  "browser": "./src/browser.js"
+  "browser": "./src/browser.js",
+  "peerDependencies": {
+    "supports-color": "^6.1.0"
+  },
+  "peerDependenciesMeta": {
+    "supports-color": {
+      "optional": true
+    }
+  }
 }

src/node.js

@@ -23,8 +23,6 @@ exports.useColors = useColors;
 exports.colors = [6, 2, 3, 4, 5, 1];
 
 try {
-	// Optional dependency (as in, doesn't need to be installed, NOT like optionalDependencies in package.json)
-	// eslint-disable-next-line import/no-extraneous-dependencies
 	const supportsColor = require('supports-color');
 
 	if (supportsColor && (supportsColor.stderr || supportsColor).level >= 2) {