README.rst: update and merged/fix issue in old repo

Merged: kendryte/kflash.py#44
Merged: kendryte/kflash.py#40
Merged: kendryte/kflash.py#39
Merged: kendryte/kflash.py#38
Fixed: kendryte/kflash.py#33

Signed-off-by: Huang Rui <vowstar@gmail.com>

Author: vowstar

README.rst

@@ -10,7 +10,7 @@ kflash, A Python-based Kendryte K210 UART ISP Utility
 .. image:: https://travis-ci.com/vowstar/kflash.py.svg?branch=master
     :target: https://travis-ci.com/vowstar/kflash.py
 
-The latest release version will put here.
+The latest release version will put here, and sync with pip.
 
 Usage
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