Add a friendly message for pip install wechaty users

[huan]

Now we are on our way to the Python Wechaty world, the code base is growing very fast under the excellent work from @wj-Mcat

And we have enabled GitHub Actions for the CI/CD: we automatically doing unit tests, and deploy our code to PyPI if the tests passed.

Now you can already do this:

$ pip install wechaty
$ python
>>> import wechaty
>>> bot = Wechaty()

However, the current wechaty module on PyPI is not functional yet, so if there's a user who wants to try Python Wechaty, they will get a Wechaty instance just not works, without any useful message.

We believe the better behavior should be: throw a message to the PyPI user when they install Wechaty and instantiated it, let them know the current progress of the Python Wechaty project, and show them the GitHub Repo of Python Wechaty so that they can come to GitHub and see what happens at here, then make a reasonable expectation.

[huan]

Done on v0.4:

$ python -m venv python3.7

$ cd python3.7
$ . bin/activate

(python3.7) $ pip install wechaty
Collecting wechaty
  Downloading https://files.pythonhosted.org/packages/a4/0c/32d4c2b9ed609f693aad9460c80aa50890d5bf78533f18bcb5a089fd6086/wechaty-0.4.0-py3-none-any.whl
Installing collected packages: wechaty
Successfully installed wechaty-0.4.0

(python3.7) $ python
Python 3.7.5 (default, Nov 20 2019, 09:21:52) 
[GCC 9.2.1 20191008] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> from wechaty import Wechaty
>>> bot = Wechaty()


Hello Python Wechaty user,

    Thank you very much for using Python Wechaty!

    Wechaty is a RPA SDK for Wechat Individual Account that can help you create a chatbot in 6 lines of Python.
    Our GitHub is at https://github.com/wechaty/python-wechaty

    Today, we are under the process of translating the TypeScript Wechaty to Python Wechaty, please see issue #11 "From TypeScript to Python in Wechaty Way - Internal Modules" at https://github.com/wechaty/python-wechaty/issues/11

    To stay tuned, watch our repository now!

    Please also feel free to leave comments in our issues if you want to contribute, testers, coders, and doc writers are all welcome!

Huan
Author of Wechaty
Mar 15, 2020

        
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