Update devDependencies (#183)

* c8     ^7.11.0  →  ^7.11.3
* grunt   ^1.4.1  →   ^1.5.3
* xo     ^0.48.0  →  ^0.49.0

Author: XhmikosR

lib/htmllint.js

@@ -30,7 +30,7 @@ function htmllint(config, done) {
       throw err;
     }
 
-    const [majorVersion, minorVersion] = java.version.split('.').map(part => Number(part));
+    const [majorVersion, minorVersion] = java.version.split('.').map(Number);
 
     if ((majorVersion !== 1 && majorVersion < 8) || (majorVersion === 1 && minorVersion < 8)) {
       throw new Error(`\nUnsupported Java version used: ${java.version}. Java 8 environment or up is required!`);