Bump approvaltests from 13.2.1 to 18.4.0#80

dependabot[bot] wants to merge 1 commit intomasterCourseOrchestra/celestadoc:masterfrom

dependabot/maven/com.approvaltests-approvaltests-18.4.0CourseOrchestra/celestadoc:dependabot/maven/com.approvaltests-approvaltests-18.4.0Copy head branch name to clipboard