Update dependencies and linting changes

[StefanBratanov]

• Update versions of most libraries and gradle plugins
• Upgrade the gradle wrapper to 7.6
• Update kotlin version from 1.6.10 to 1.6.21
• Replace jmh initialization with a me.champeau.jmh gradle plugin
• Linting changes to files based on the lintKotlin task
• Change the jvmTarget, sourceCompatibility and targetCompatibility to Java 11 (align with the README.md saying Java 11 is needed.)
• Small build.gradle nits suggested by IntelliJ
• Change the two dependency badges in the README.md with one provided by cloudsmith

fixes #242

[Nashatyrev]

All looks good to me except I would not upgrade Kotlin version unless it's strictly necessary

• Kotlin 1.8 is still marked as 'experimental'
• Kotlin doesn't maintain strict backward compatibility. That may also break existing lib user's codebase
• Kotlin is still not that stable as Java.

I also had some doubts regarding usage of me.champeau.jmh gradle plugin as we had some issues with it in Teku and finally replaced it with a custom code (Consensys/teku#4817). But I tried running JMH from IDEA and from CLI and didn't noticed any problems. So we could apply this change for now and revert back in case if anything goes wrong.

[StefanBratanov]

All looks good to me except I would not upgrade Kotlin version unless it's strictly necessary

• Kotlin 1.8 is still marked as 'experimental'
• Kotlin doesn't maintain strict backward compatibility. That may also break existing lib user's codebase
• Kotlin is still not that stable as Java.

I also had some doubts regarding usage of me.champeau.jmh gradle plugin as we had some issues with it in Teku and finally replaced it with a custom code (Consensys/teku#4817). But I tried running JMH from IDEA and from CLI and didn't noticed any problems. So we could apply this change for now and revert back in case if anything goes wrong.

Thanks Anton for the review. What is latest version of Kotlin which is not experimental or just reverting back to 1.6 makes more sense?

[Nashatyrev]

What is latest version of Kotlin which is not experimental or just reverting back to 1.6 makes more sense?

I would leave 1.6 unless there is a need for upgrade

[StefanBratanov]

What is latest version of Kotlin which is not experimental or just reverting back to 1.6 makes more sense?

I would leave 1.6 unless there is a need for upgrade

Cool. Makes sense. I changed it to the latest version of 1.6. Had to downgrade couple of libraries to previous versions.

[Nashatyrev]

I believe no need to revert this lib back to stdlib-jdk8 as we switched to Java-11 target

[StefanBratanov]

From what I read from Kotlin 1.8 stdlib-jdk8 is merged into kotlin-stdlib . Otherwise, it is preferred to use stdlib-jdk8 to make use of the jdk8 extensions.

[Nashatyrev]

Had to downgrade couple of libraries to previous versions.

Yep, that's the downside of not upgrade. Seems like no critical libs has to be downgraded though

[StefanBratanov]

Just force pushed a cleaner commit without a lot of linting changes (which applies only to the later versions of Kotlin and the kotlinter)