Merge pull request AR-js-org#662 from ma2yama/fixPrettier

Fix Prettier configuration file name

Author: nickw1

.prettierc.json

@@ -0,0 +1,7 @@
+{
+  "trailingComma": "all",
+  "tabWidth": 2,
+  "printWidth": 80,
+  "semi": true,
+  "singleQuote": false
+}