chore(package): update prettier to version 2.0.5

Closes #246

Author: greenkeeper[bot]

package.json

@@ -101,7 +101,7 @@
     "graphql-tester": "0.0.5",
     "jest": "^24.9.0",
     "jest-sonar-reporter": "^2.0.0",
-    "prettier": "^1.19.1",
+    "prettier": "^2.0.5",
     "shelljs": "^0.8.3",
     "supertest": "^4.0.2",
     "ts-jest": "^24.2.0",