fix: Lock gruntify-eslint version to fix build errors (#42)

* Lock version of gruntify-eslint (and grunt-replace)

The current repository is compatible with gruntify-eslint 3.1.0.
`*` resolves to version 4.0.0., which bumps its eslint dependency
from 3.x to 4.x, which in turn causes linting errors.

To get the default check-out to pass, lock the dependencies to
known-compatible versions.

* Bump gruntify-eslint to 4.0.0 + fix lint error

Bump gruntify-eslint to 4.0.0, which depends on eslint ^4.0.0,
and fix the lint error that appeared.

Gruntfile.js

@@ -33,8 +33,8 @@ module.exports = function(grunt) {
               match: /\{\/\* include\("(.*?)"\) \*\/\}/,
               replacement: (match, filename) => {
                 return grunt.file.read(filename)
-                            .replace(/\n$/, "")
-                            .replace(/^[^{]/gm, "    $&");
+                  .replace(/\n$/, "")
+                  .replace(/^[^{]/gm, "    $&");
               },
             },
             {

package.json

@@ -25,8 +25,8 @@
     "grunt-babel": "^6.0.0",
     "grunt-contrib-concat": "^1.0.1",
     "grunt-coveralls": "^1.0.1",
-    "grunt-replace": "*",
-    "gruntify-eslint": "*",
+    "grunt-replace": "^1.0.1",
+    "gruntify-eslint": "^4.0.0",
     "istanbul-lib-instrument": "^1.1.3",
     "jsdom": "^9.6.0",
     "mocha": "^3.1.0",