Bumpp assertj-core version to 3.15.0
<javadocAdditionalOptions>-html5 --allow-script-in-comments --no-module-directories</javadocAdditionalOptions>
<!-- guava 21+ is for java 8 -->
<guava.version>28.1-jre</guava.version>
- <assertj-core.version>3.14.0</assertj-core.version>
+ <assertj-core.version>3.15.0</assertj-core.version>
</properties>
<dependencies>
