Update nyc and ignore HTML coverage reports
diff --git a/.gitignore b/.gitignore
index fd547b8..ffddc1a 100644
--- a/.gitignore
+++ b/.gitignore
@@ -16,3 +16,4 @@
 node_modules/*
 node_module/.bin/*
 .nyc_output/
+coverage/
diff --git a/package.json b/package.json
index db8a1b4..fb46613 100644
--- a/package.json
+++ b/package.json
@@ -44,7 +44,7 @@
     "eslint-plugin-promise": "^3.5.0",
     "eslint-plugin-standard": "^3.0.1",
     "jasmine": "^3.1.0",
-    "nyc": "^11.7.3",
+    "nyc": "^12.0.2",
     "rewire": "^4.0.1"
   },
   "scripts": {