fix(prettier): add parser, filePath (#553)
fix(prettier): add parser, filePath (#553)

**What kind of change does this PR introduce?**
Bugfix

**Did you add tests for your changes?**
No

**If relevant, did you update the documentation?**
No

**Summary**
![image](https://user-images.githubusercontent.com/5961873/42949683-ef845284-8b8f-11e8-9f3a-d8d4c673a542.png)

Prettier shows warning currently that filePath and parser aren't specified.
It would throw errors in future major versions. [#4828](https://github.com/prettier/prettier/pull/4528)

This PR cleans the warning shown in the above image.

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**Does this PR introduce a breaking change?**
No

**Other information**
No
webpack/webpack-cli,webpack/webpack-cli,webpack/webpack-cli