Issue with gradle configurations like 'implementation', 'testImplementation'

[vlipovetskii]

I strive to leverage new gradle configurations like 'implementation', 'testImplementation', since 'compile' and 'testCompile' are deprecated. It looks that vaadin-plugin doesn't support the new gradle configurations, since gretty fails to launch war. I have discovered in the GradleVaadinPlugin.groovy fragment, that I think, confirms my suggestion:
`…
// Needed so bootRepackage can include all dependencies in Jar
conf.extendsFrom(
project.configurations['compile'],
project.configurations['runtime'],
project.configurations[CONFIGURATION_PUSH],
project.configurations[CONFIGURATION_CLIENT_COMPILE]
)
…

`
As a workaround I temporarily added 'compile' and 'testCompile'.

Possible, that issue of @mvysny (#501) and mine are connected ? I leverage karibu-dsl by @mvysny.

[johndevs]

Yes, right now the new implementation configurations are not supported.

Unfortunately, it is a breaking change which means that either we have to release a non-backwards compatible plugin or continue to use compile configurations as they work in both new and old versions of Gradle.