Upgrade diktat to 1.2.0

[nulls]

Bump default diktat version to latest 1.1.0 -> 1.2.0

It closes saveourtool/diktat#1399

[nulls]

Hi,

We (diktat) released the new version 1.2.0. It has breaking changes and requires changes in spotless.
This PR with supporting these changes.

[orchestr7]

Probably there can be some problems with backward compatibility.
Is there any chance to raise an error for older versions of diktat? @nedtwigg

[nedtwigg]

If the code now requires 1.2.0 or greater, that's fine, but:

• it needs to be marked in the changelogs
• DiktatStep.create needs to parse the version number, and proactively throw an error if less than 1.2.0 (BadSemver should make this pretty easy.)

[nedtwigg]

(Also you need to run gradlew spotlessApply)

[nulls]

@nedtwigg, new version of diktat requires ktlint:0.46.1.
If spotless run with ktlint < 0.46.1 and diktat > 1.2.0, what's version of ktlint will be on classpath?

As I can see, there is com.diffplug.spotless.FeatureClassLoader which is used to load jars for FormatterStep. Does it mean that dependencies for formatters are isolated?

[nedtwigg]

Correct, Spotless classloaders are isolated. BTW, this PR bumps diktat to 1.2.1, which seems to not exist. I'm going to downgrade this to 1.2.0

https://search.maven.org/artifact/org.cqfn.diktat/diktat-rules

[nedtwigg]

Released in plugin-gradle 6.8.0 and plugin-maven 2.23.0.