Bump ansys-mapdl-core from 0.68.4 to 0.68.6

Bumps [ansys-mapdl-core](https://github.com/ansys/pymapdl) from 0.68.4 to 0.68.6.
- [Release notes](https://github.com/ansys/pymapdl/releases)
- [Changelog](https://github.com/ansys/pymapdl/blob/main/CHANGELOG.md)
- [Commits](ansys/pymapdl@v0.68.4...v0.68.6)

---
updated-dependencies:
- dependency-name: ansys-mapdl-core
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

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

pyproject.toml

@@ -74,7 +74,7 @@ doc = [
 	# pyansys dependencies for sphinx gallery examples
 	"ansys-fluent-core==0.26.0",
 	"ansys-dpf-core==0.13.0",
-	"ansys-mapdl-core==0.68.4",
+	"ansys-mapdl-core==0.68.6",
 ]
 style = [
 	# NB: ensure these remain synced with .pre-commit-config.yaml