pyproject.toml: prevent sphinxcontrib-devhelp incompatibilities

sphinxcontrib-devhelp>=1.0.3 depends on Sphinx>=5. This wasn't an issue
until now, since labgrid pins Sphinx==4.2.0 on stable. With
sphinxcontrib-devhelp>=1.0.6, this explicit dependency was dropped to
prevent cyclic dependencies, so the latest version gets installed,
although it's clearly incompatible. This is detected during runtime:

  The sphinxcontrib.devhelp extension used by this project needs at least Sphinx v5.0; it therefore cannot be built with this version.

So set sphinxcontrib-devhelp to a version lower than when the explicit
Sphinx dependency was dropped.

Signed-off-by: Bastian Krause <bst@pengutronix.de>

Author: Bastian-Krause

pyproject.toml

@@ -58,6 +58,7 @@ doc = [
     "docutils==0.17.1",
     "Sphinx==4.2.0",
     "sphinxcontrib-applehelp<1.0.8",
+    "sphinxcontrib-devhelp<1.0.5",
     "sphinx_rtd_theme==1.0.0",
 ]
 docker = ["docker==5.0.2"]
@@ -102,6 +103,7 @@ dev = [
     "docutils==0.17.1",
     "Sphinx==4.2.0",
     "sphinxcontrib-applehelp<1.0.8",
+    "sphinxcontrib-devhelp<1.0.5",
     "sphinx_rtd_theme==1.0.0",
 
     # labgrid[docker]