Bump pysigma from 0.11.4 to 0.11.6

Bumps [pysigma](https://github.com/SigmaHQ/pySigma) from 0.11.4 to 0.11.6.
- [Release notes](https://github.com/SigmaHQ/pySigma/releases)
- [Commits](SigmaHQ/pySigma@v0.11.4...v0.11.6)

---
updated-dependencies:
- dependency-name: pysigma
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

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

requirements.txt

@@ -7,7 +7,7 @@ mock==4.0.3
 psutil==5.9.8
 pycvesearch==1.2
 pydantic==1.10.8
-pysigma==0.11.4
+pysigma==0.11.6
 pysigma-backend-splunk==1.1.0
 pytest==7.4.4
 PyYAML>=5.4.1