chore(deps): pin dependency prettier to 1.18.2

Author: renovate-bot

package.json

@@ -60,7 +60,7 @@
     "karma-coverage-istanbul-reporter": "2.0.5",
     "karma-jasmine": "2.0.1",
     "karma-jasmine-html-reporter": "1.4.0",
-    "prettier": "~1.18.2",
+    "prettier": "1.18.2",
     "protractor": "5.4.2",
     "ts-node": "8.0.2",
     "tslint": "5.18.0",