Update dependency prettier to v1.17.0 (#18)

Author: renovate[bot]

package.json

@@ -13,7 +13,7 @@
     "@sourcegraph/prettierrc": "2.2.0",
     "@types/node": "latest",
     "opn-cli": "4.0.0",
-    "prettier": "1.16.4",
+    "prettier": "1.17.0",
     "tslint": "5.15.0",
     "tslint-config-prettier": "1.18.0"
   },

yarn.lock

@@ -1083,10 +1083,10 @@ pify@^3.0.0:
   resolved "https://registry.yarnpkg.com/pify/-/pify-3.0.0.tgz#e5a4acd2c101fdf3d9a4d07f0dbc4db49dd28176"
   integrity sha1-5aSs0sEB/fPZpNB/DbxNtJ3SgXY=
 
-prettier@1.16.4:
-  version "1.16.4"
-  resolved "https://registry.yarnpkg.com/prettier/-/prettier-1.16.4.tgz#73e37e73e018ad2db9c76742e2647e21790c9717"
-  integrity sha512-ZzWuos7TI5CKUeQAtFd6Zhm2s6EpAD/ZLApIhsF9pRvRtM1RFo61dM/4MSRUA0SuLugA/zgrZD8m0BaY46Og7g==
+prettier@1.17.0:
+  version "1.17.0"
+  resolved "https://registry.yarnpkg.com/prettier/-/prettier-1.17.0.tgz#53b303676eed22cc14a9f0cec09b477b3026c008"
+  integrity sha512-sXe5lSt2WQlCbydGETgfm1YBShgOX4HxQkFPvbxkcwgDvGDeqVau8h+12+lmSVlP3rHPz0oavfddSZg/q+Szjw==
 
 process-nextick-args@~2.0.0:
   version "2.0.0"