Merge branch 'v2.1-dev' into 'v2.x-master'

Change CI image from java:11-jdk to openjdk:11-jdk

See merge request !11
3 jobs for v2.x-master in 1 minute and 20 seconds (queued for 50 seconds)
Name Stage Failure
failed
build Build
Deprecated Gradle features were used in this build, making it incompatible with Gradle 7.0.
Use '--warning-mode all' to show the individual deprecation warnings.
https://help.gradle.org

BUILD FAILED in 17sSee https://docs.gradle.org/6.6.1/userguide/command_line_interface.html#sec:command_line_warnings
5 actionable tasks: 5 executed

Cleaning up project directory and file based variables
ERROR: Job failed: exit code 1