chore(package): update @sourcegraph/prettierrc to version 2.0.0 (#398)

Author: greenkeeper[bot]

package.json

@@ -59,7 +59,7 @@
   "devDependencies": {
     "@semantic-release/npm": "^2.0.0",
     "@semantic-release/github": "^2.0.0",
-    "@sourcegraph/prettierrc": "^1.1.0",
+    "@sourcegraph/prettierrc": "^2.0.0",
     "@sourcegraph/tsconfig": "^1.0.0",
     "@sourcegraph/tslint-config": "^9.0.2",
     "@types/chai": "^4.0.0",