Bump weasyprint from 68.0 to 68.1 in /backend-agent

Bumps [weasyprint](https://github.com/Kozea/WeasyPrint) from 68.0 to 68.1.
- [Release notes](https://github.com/Kozea/WeasyPrint/releases)
- [Changelog](https://github.com/Kozea/WeasyPrint/blob/main/docs/changelog.rst)
- [Commits](Kozea/WeasyPrint@v68.0...v68.1)

---
updated-dependencies:
- dependency-name: weasyprint
  dependency-version: '68.1'
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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

Author: dependabot[bot]

backend-agent/pyproject.toml

@@ -30,7 +30,7 @@ dependencies = [
     'art==6.5',
     'pandas==2.3.3',
     'ollama==0.6.1',
-    'weasyprint==68.0',
+    'weasyprint==68.1',
     'pyrit==0.9.0',
     'codeattack @ git+https://github.com/marcorosa/CodeAttack',
     'gptfuzzer @ git+https://github.com/marcorosa/GPTFuzz@no-vllm',