Update dev requirements based on last release

Signed-off-by: Bert van Hall <bert.vanhall@gmx.de>

Author: The-42

requirements-dev.txt

@@ -1,6 +1,6 @@
 # requirements for development and release process
-twine
-docutils
-sphinx
-readme_renderer     # to check long description in setup.py: https://github.com/pypa/readme_renderer
-                    # python setup.py check -r -s
+twine               # PyPi interaction, long description check in setup.py (twine check dist/intelhex-*.whl)
+rst2html            # documentation generation
+sphinx              # documentation generation
+docutils            # sphinx and rest2html dependency
+pdoc                # API documentation