docs: add requirements to README

Signed-off-by: Igor Gnatenko <i.gnatenko.brain@gmail.com>
trivial: fix style with PEP8 (without E501)

process-simple-patch.py:2:1: E265 block comment should start with '# '
process-simple-patch.py:160:5: F841 local variable 'isPackager' is assigned to but never used
process-simple-patch.py:181:5: F841 local variable 'out' is assigned to but never used

Signed-off-by: Igor Gnatenko <i.gnatenko.brain@gmail.com>