Invalid file path pattern on Windows

A student trying to run the simulator in [Caffeine](https://github.com/ben-manes/caffeine) faced a compilation error because of a malformed regex. I reviewed the Gradle build configuration ([build](https://github.com/ben-manes/caffeine/blob/master/caffeine/build.gradle), [options](https://github.com/ben-manes/caffeine/blob/master/gradle/codeQuality.gradle)) and do not see a mistake there. Since I am not very familiar with Windows my debugging is limited.

I was able to reproduce his problem by running a Windows 10 [trial virtual machine](https://developer.microsoft.com/en-us/windows/downloads/virtual-machines/). The attached screenshot is from ".\gradlew.bat simulator:run -S". I disabled the errorprone plugin and provided the student those steps so that his project is unblocked.