Bump rxjava from 3.0.11 to 3.0.12

Bumps rxjava from 3.0.11 to 3.0.12.

Release notes

Sourced from rxjava's releases.

3.0.12

Maven JavaDocs

Bugfix

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

Documentation

• Fix wrong reference in Single.flattenStreamAsObservable javadoc. (#7206)
• Fix style violating Javadoc. (#7210)

Other

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

3.0.12-RC1

Pre-release experiment due to changes in the build setup in #7219.

Commits

• 11b50a5 Modernize gradle plugin block, change maven to maven-publish (#7219)
• c38ea99 Bump guava from 30.1-jre to 30.1.1-jre (#7216)
• 269bb0f Fix POM_URL (#7214)
• bdf13a1 Fix intermittently failing unit tests (#7213)
• e600b53 3.x: CompositeException.printStackTrace to write directly into PS/PW (#7212)
• 5c0ca03 Added Javadoc checks to Checkstyle. Fix violating Javadoc. (#7210)
• ea8c183 Bump gradle to 6.8.3 & optimize gradle config (#7207)
• 1a12855 3.x: Upgrade Gradle to 6.8.3 (#7208)
• f75498c 3.x: Fix wrong reference in Single.flattenStreamAsObservable javadoc (#7206)
• See full diff in compare view