update for pyrogram v2

[qqwbarta]

fixes #67

[mxkmn]

Thank you, it works, but you also need to update version in requirements.txt

[qqwbarta]

I might be wrong but one downside of this version is that now it only deletes messages, previously it deleted all the reactions and group events like entering the group, leaving and so on

[gurland]

@qqwbarta Thank you for your contribution! I think this PR is a great starter to migrate the project to the newest version of Pyrogram.

Didn't even know that the scipt was able to remove reactions. However, we have to preserve functional backward compatibility, so that all reactions are deleted as well.

We should also think on performance impact meaning that using new high-level Pyrogram APIs we may need to send additional requests to retract reactions using send_reaction method

[lbgracioso]

Thank you! It worked.