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

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


Updates `ansys-sphinx-theme` from 1.2.4 to 1.2.6
- [Release notes](https://github.com/ansys/ansys-sphinx-theme/releases)
- [Commits](ansys/ansys-sphinx-theme@v1.2.4...v1.2.6)

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

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

Author: dependabot[bot]

pyproject.toml

@@ -42,7 +42,7 @@ tests = [
 ]
 
 doc = [
-    "ansys-sphinx-theme==1.2.4",
+    "ansys-sphinx-theme==1.2.6",
     "jupyter_sphinx==0.5.3",
     "jupytext==1.16.6",
     "nbsphinx==0.9.6",