Bump org.xhtmlrenderer:flying-saucer-pdf from 9.5.2 to 9.7.1

Bumps [org.xhtmlrenderer:flying-saucer-pdf](https://github.com/flyingsaucerproject/flyingsaucer) from 9.5.2 to 9.7.1.
- [Release notes](https://github.com/flyingsaucerproject/flyingsaucer/releases)
- [Changelog](https://github.com/flyingsaucerproject/flyingsaucer/blob/main/CHANGELOG.md)
- [Commits](flyingsaucerproject/flyingsaucer@v9.5.2...v9.7.1)

---
updated-dependencies:
- dependency-name: org.xhtmlrenderer:flying-saucer-pdf
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>

pdf/build.gradle

@@ -4,7 +4,7 @@ configurations {
 }
 
 ext {
-  FLYING_SOURCER_VERSION = '9.5.2'
+  FLYING_SOURCER_VERSION = '9.7.1'
   YAHP_VERSION = 1.3
 }