dependabot maven(deps): bump checkstyle from 10.3.4 to 10.4

Bumps checkstyle from 10.3.4 to 10.4.

Release notes

Sourced from checkstyle's releases.

checkstyle-10.4

Checkstyle 10.4 - https://checkstyle.org/releasenotes.html#Release_10.4

Breaking backward compatibility:

#12101 - Checker.localeLanguage property work strange with system property user.language #12102 - Remove custom cache in Violation.java. It was extra cache for resource bundle cache for messages.

Bug fixes:

#11920 - False Positive: UnusedLocalVariableCheck

Commits

• 8bb88b7 [maven-release-plugin] prepare release checkstyle-10.4
• 5f165db doc: releasenotes 10.4
• 9b4e1a6 minor: Bump release version to 10.4
• 3bbdf40 Issue #12228: Changes in the overview section applied
• 0ad54c5 Issue #11747: Migrate codenarc to travis CI
• 6704023 dependency: bump maven-shade-plugin from 3.4.0 to 3.4.1
• 716ae3d config: upgrade appveyor maven to 3.8.6
• 7215503 Issue #12319: validate PR number when commit is for PR
• e2e9792 Issue #12259: Create CI task to fail PR if merge commit exists
• 28d8be3 Issue #12311: checker-framework.groovy depends too much on name of repo
• Additional commits viewable in compare view