Bump prettier from 1.14.3 to 1.15.2 (forem#1094) [ci skip]

Bumps [prettier](https://github.com/prettier/prettier) from 1.14.3 to 1.15.2.
- [Release notes](https://github.com/prettier/prettier/releases)
- [Changelog](https://github.com/prettier/prettier/blob/master/CHANGELOG.md)
- [Commits](prettier/prettier@1.14.3...1.15.2)

Signed-off-by: dependabot[bot] <support@dependabot.com>

package.json

@@ -72,7 +72,7 @@
     "lint-staged": "^8.0.4",
     "preact-render-spy": "^1.3.0",
     "preact-render-to-json": "^3.6.6",
-    "prettier": "^1.14.3",
+    "prettier": "^1.15.2",
     "webpack-dev-server": "^2.11.3"
   },
   "dependencies": {

yarn.lock

@@ -8572,10 +8572,10 @@ preserve@^0.2.0:
   resolved "https://registry.yarnpkg.com/preserve/-/preserve-0.2.0.tgz#815ed1f6ebc65926f865b310c0713bcb3315ce4b"
   integrity sha1-gV7R9uvGWSb4ZbMQwHE7yzMVzks=
 
-prettier@^1.14.3:
-  version "1.14.3"
-  resolved "https://registry.yarnpkg.com/prettier/-/prettier-1.14.3.tgz#90238dd4c0684b7edce5f83b0fb7328e48bd0895"
-  integrity sha512-qZDVnCrnpsRJJq5nSsiHCE3BYMED2OtsI+cmzIzF1QIfqm5ALf8tEJcO27zV1gKNKRPdhjO0dNWnrzssDQ1tFg==
+prettier@^1.15.2:
+  version "1.15.2"
+  resolved "https://registry.yarnpkg.com/prettier/-/prettier-1.15.2.tgz#d31abe22afa4351efa14c7f8b94b58bb7452205e"
+  integrity sha512-YgPLFFA0CdKL4Eg2IHtUSjzj/BWgszDHiNQAe0VAIBse34148whfdzLagRL+QiKS+YfK5ftB6X4v/MBw8yCoug==
 
 pretty-error@^2.0.2:
   version "2.1.1"