Bump com.itextpdf:html2pdf from 5.0.5 to 6.0.0 in /server

Bumps [com.itextpdf:html2pdf](https://github.com/itext/i7j-pdfhtml) from 5.0.5 to 6.0.0.
- [Release notes](https://github.com/itext/i7j-pdfhtml/releases)
- [Commits](itext/itext-pdfhtml-java@5.0.5...6.0.0)

---
updated-dependencies:
- dependency-name: com.itextpdf:html2pdf
  dependency-type: direct:production
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <[email protected]>

server/build.gradle

@@ -47,7 +47,7 @@ dependencies {
 	implementation "com.github.vladimir-bukhtoyarov:bucket4j-core:8.0.1"
 	implementation "org.mnode.ical4j:ical4j:4.0.5"
 	implementation "com.itextpdf:itext-core:8.0.5"
-	implementation "com.itextpdf:html2pdf:5.0.5"
+	implementation "com.itextpdf:html2pdf:6.0.0"
 	implementation "com.auth0:java-jwt:4.4.0"
 
 	// use newest version of commons-compress to avoid security issues through outdated dependencies