would be nice to add python3 as prerequisite as readme

[mosheviGsxr]

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Description

currently when trying to install IDB on mac i experienced the following problem:
after installing
brew install idb-companion.
and when trying to install
pip3.6 install fb-idb
i got error saying that - pip3 is not recognized

Reproduction

try to follow README instructions on MAC where you don't have python installed
you will be faced with error

Solution

Would be nice to add something like
you need python3 installed on your machine
brew install python3

Additional Information

• idb revision: [FILL THIS OUT]