3.0.12 release preparations

[akarnokd]

Version 3.0.11 - March 6, 2021 (Maven)

JavaDocs

Bugfix

• CompositeException.printStackTrace to write directly into PrintStream/PrintWriter. (3.x: CompositeException.printStackTrace to write directly into PrintStream/PrintWriter #7212)

Documentation

• Fix wrong reference in Single.flattenStreamAsObservable javadoc. (3.x: Fix wrong reference in Single.flattenStreamAsObservable javadoc #7206)
• Fix style violating Javadoc. (Added Javadoc checks to Checkstyle. Fix violating Javadoc. #7210)

Other

• Fix POM_URL (Fix POM_URL #7214)
• Upgrade Gradle to 6.8.3 (3.x: Upgrade Gradle to 6.8.3 #7208)
• Bump gradle to 6.8.3 & optimize gradle config (Bump gradle to 6.8.3 & optimize gradle config #7207)
• Added Javadoc checks to Checkstyle. Fix violating Javadoc. (Added Javadoc checks to Checkstyle. Fix violating Javadoc. #7210)
• Modernize gradle plugin block, change maven to maven-publish (Modernize gradle plugin block, change maven to maven-publish #7219)

[benjamintboyle]

I don't think there should be any issues, but I'd like to point out that changes to the Gradle build script could cause issues with the release. Specifically the change from the 'maven' to 'maven-publish' plugin. This will essentially be the first end-to-end test.

[akarnokd]

I'll do an RC release first.

Also Dependabot did not offer a PR for mockito 3.9.0, maybe it got confused by the updated build gradle.

[akarnokd]

It worked. Also Dependabot did post after all.

[akarnokd]

Closing via v3.0.12.