build(deps): bump ansys-sphinx-theme in the dev-dependencies group

Bumps the dev-dependencies group with 1 update: [ansys-sphinx-theme](https://github.com/ansys/ansys-sphinx-theme).


Updates `ansys-sphinx-theme` from 1.1.3 to 1.1.6
- [Release notes](https://github.com/ansys/ansys-sphinx-theme/releases)
- [Commits](ansys/ansys-sphinx-theme@v1.1.3...v1.1.6)

---
updated-dependencies:
- dependency-name: ansys-sphinx-theme
  dependency-type: direct:production
  update-type: version-update:semver-patch
  dependency-group: dev-dependencies
...

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

Author: dependabot[bot]

pyproject.toml

@@ -40,7 +40,7 @@ tests = [
     "gitpython==3.1.43",
 ]
 doc = [
-    "ansys-sphinx-theme==1.1.3",
+    "ansys-sphinx-theme==1.1.6",
     "numpydoc==1.8.0",
     "sphinx==8.1.3",
     "sphinx-autoapi==3.3.2",