Add `eslint-plugin-mocha`

Allows us to set various lint rules for our tests.

package.json

@@ -87,6 +87,7 @@
     "eslint": "^4.14.0",
     "eslint-config-airbnb-base": "^12.1.0",
     "eslint-plugin-import": "^2.8.0",
+    "eslint-plugin-mocha": "^4.12.1",
     "eslint-plugin-more": "^0.3.1",
     "extract-zip": "^1.6.6",
     "grunt": "^1.0.1",

yarn.lock

@@ -1693,6 +1693,12 @@ eslint-plugin-import@^2.8.0:
     minimatch "^3.0.3"
     read-pkg-up "^2.0.0"
 
+eslint-plugin-mocha@^4.12.1:
+  version "4.12.1"
+  resolved "https://registry.yarnpkg.com/eslint-plugin-mocha/-/eslint-plugin-mocha-4.12.1.tgz#dbacc543b178b4536ec5b19d7f8e8864d85404bf"
+  dependencies:
+    ramda "^0.25.0"
+
 eslint-plugin-more@^0.3.1:
   version "0.3.1"
   resolved "https://registry.yarnpkg.com/eslint-plugin-more/-/eslint-plugin-more-0.3.1.tgz#ff688fb3fa8f153c8bfd5d70c15a68dc222a1b31"
@@ -4329,6 +4335,10 @@ querystring@0.2.0:
   version "0.2.0"
   resolved "https://registry.yarnpkg.com/querystring/-/querystring-0.2.0.tgz#b209849203bb25df820da756e747005878521620"
 
+ramda@^0.25.0:
+  version "0.25.0"
+  resolved "https://registry.yarnpkg.com/ramda/-/ramda-0.25.0.tgz#8fdf68231cffa90bc2f9460390a0cb74a29b29a9"
+
 randomatic@^1.1.3:
   version "1.1.7"
   resolved "https://registry.yarnpkg.com/randomatic/-/randomatic-1.1.7.tgz#c7abe9cc8b87c0baa876b19fde83fd464797e38c"