diktat-gradle-plugin: add support for multiple reporters

[illarionov]

Now you can set only one reporter in the diktat-gradle-plugin plugin using the report configuration parameter or by setting
the "githubActions = true".
Setting the reporter to sarif disables error reporting to stdout.
It would be nice if we could enable both of them.

[nulls]

Hi @illarionov, thanks for raising the issue. We will look into it

Note: it can be done in scope #1472

[nulls]

Hi @illarionov,

We supported it in 2.0.0 (will be released soon).

It will require changes in diktat configuration. Example:

// enables sarif reporting to a single file by flag: `diktat.githubActions`
githubActions = findProperty("diktat.githubActions")?.toString()?.toBoolean() ?: false
reporters {
    // enables plain reporters with output to stdout
    plain()
}

README.md will be updated accordingly