Bump gradle-intellij-plugin version

[gajwani]

The old version was causing problems when downloading the
kotlin plugin due to the server now including query string
parameters in the downloaded .zip filename

See issue: JetBrains/intellij-platform-gradle-plugin#201

Particularly, if we download this project fresh and run gradle we get an error like this:

 → gradle

FAILURE: Build failed with an exception.

* What went wrong:
A problem occurred configuring project ':plugin'.
> Invalid type of downloaded plugin: /var/folders/7s/mdwxcrws4ng1km3smqrh6zrc0000gn/T/intellij474753869254598434/kotlin-plugin-1.0.4-release-IJ2016.1-112.zip?updateId=28547&pluginId=6954

* Try:
Run with --stacktrace option to get the stack trace. Run with --info or --debug option to get more log output.

BUILD FAILED

Total time: 11.46 secs

Note that this problem may not occur if you have a cached kotlin-plugin from previous builds in ~/.gradle -- it needs to be downloading a fresh copy