Drop built-in Flow type definition

I don't want to be responsible for maintaining it.

Submit it to https://github.com/flow-typed/flow-typed if you need it.

package.json

@@ -8,14 +8,13 @@
 		"node": ">=8"
 	},
 	"scripts": {
-		"test": "xo && nyc ava && tsd && flow",
+		"test": "xo && nyc ava && tsd",
 		"bench": "matcha benchmark.js"
 	},
 	"files": [
 		"index.js",
 		"templates.js",
-		"index.d.ts",
-		"index.js.flow"
+		"index.d.ts"
 	],
 	"keywords": [
 		"color",
@@ -50,17 +49,11 @@
 		"ava": "^1.4.1",
 		"coveralls": "^3.0.3",
 		"execa": "^1.0.0",
-		"flow-bin": "^0.98.0",
 		"import-fresh": "^3.0.0",
 		"matcha": "^0.7.0",
 		"nyc": "^14.0.0",
 		"resolve-from": "^5.0.0",
 		"tsd": "^0.7.2",
 		"xo": "^0.24.0"
-	},
-	"xo": {
-		"ignores": [
-			"test/_flow.js"
-		]
 	}
 }