Migrate to python3?

[hosiet]

Python 2 has reached end-of-life for years. However, megadown is still using scripts written for python 2. This makes megadown unusable on newer Linux systems where python2 is not provided.

It would be great if upstream could examine compatibility against python3 and update scripts to use python3 by default.

[pabs3]

Looks like the fix for this is trivial, just replace "python" with "python3", possibly adding a fallback to python or python2 when python3 is missing.