Checkstyle 8.18

[Roman Ivanov]

Checkstyle 8.18 - https://checkstyle.org/releasenotes.html#Release_8.18

Breaking backward compatibility:

  Disable loading external DTDs by default, create system property to activate it
  IllegalType: rename "format" property to "illegalAbstractClassNameFormat"
  AnnotationLocation: Remove unused tokens
  Command Line arguments should be allow to exclude a file

New:

  ArrayTypeStyle: add support for brackets in method definition after parameters
  new filter SuppressionXpathSingleFilter

Bug fixes:

  AnnotationLocation: named parameters must be considered parameters.
  JavadocStyleCheck crashes for some Javadoc comments with HTML comments
  Incorrect warning for empty lambda bodies with google_checks.xml
  FinalLocalVariable: IllegalStateException
  Slowdown with UnusedImportsCheck

Notes:

  review TreeWalker.setupChild method for exceptional cases
  Remove powermock
  refactoring in configs
  update to picocli 3.9.1 result in UT MainTest.testNonExistentOutputFormat failure
  Negate SuppressElement.accept
  Code samples for Naming Checks
  Rename Filters which aren't module filters to FilterElement
  doc: add File Filter section in extending.xml
  Cache: file skipped on 2nd run when exception happened on it in first run
  Move UTF-8 limitation info in documentation
  use ForbidAnnotationElementValueCheck from sevntu.checkstyle
  minor: solved pitest issues with ImportOrderCheck
  Pitest: add new mutator REMOVE_CONDITIONALS
  Add build instructions to README
  Indentation: indentation level is being corrupted in class fields
  doc: Fixed grammar errors