Windows dependency json-protobuf cant be installed

[thomass4t]

Hello,
I try to build the sources on windows according to the instructions at
https://nsclient.org/docs/about/build/

However, when I try to install the dependencies, I get the following error

   + Executing: pip install json-protobuf
DEPRECATION: Python 2.7 reached the end of its life on January 1st, 2020. Please upgrade your Python as Python 2.7 is no longer maintained. pip 21.0 will drop support for Python 2.7 in January 2021. More details about Python 2 support in pip can be found at https://pip.pypa.io/en/latest/development/release-process/#python-2-support pip 21.0 will remove support for this functionality.
ERROR: Could not find a version that satisfies the requirement json-protobuf (from versions: none)
ERROR: No matching distribution found for json-protobuf
 ! Failed to execute: pip install json-protobuf (1)
FAILURE

The only package of json-protobuf which I could find is:
https://pypi.org/project/json-protobuf/

But this is for python >= 3.6
The documentation says, I need python 2.7 and with this version I couldn't find a suitable package for windows.

I try to compile CheckSystem.dll and this only works on windows, as far as I have seen.

Any hint how I can continue and compile with windows (VS 2017)?