Enforce UTF-8 as Javadoc encoding

[gesellix]

The Javadoc task (or publishing) fails when running on Windows with "unmappable character for encoding Cp1252" at

testcontainers-java/core/src/main/java/org/testcontainers/DockerClientFactory.java

Line 243 in 29aa84d

log.error("\u274c {}", message);

The patch includes a version change for the com.gradle.common-custom-user-data-gradle-plugin, too, because 1.8.0 can't be found.

[kiview]

The 1.8.0 issue is so weird, wonder how this happened.

Edit:
Oh, this came in through a dependabot merge, very strange it was not caught on CI before.

[gesellix]

Yeah, I'm also confused and maybe the cause is somewhere at jcenter 🤷

[kiview]

Thanks, @gesellix and thanks for fixing master 🙇

[kiview]

@gesellix FYI I just talked with some folks at Gradle and indeed, there used to be a 1.8.0 version, that was republished as 1.8 yesterday, so that explains it. Thanks for helping out on this 😇

[gesellix]

Sure thing (no one wants a broken master 😉) and thanks for the update @kiview !