add bash completion for options added in v2.0.0

new major version 2.0.0

This release adds support for generating and copying TOTP/HOTP, opening
URLs, using skim and fzy in addition to fzf, and the ability to specify
custom keys for username and URL. It also fixes a few bugs in parsing
data and copy pasting data on Xorg.

fix help menu not printing extension name

fix the semver, should've paid more attention

update documentation, fix Makefile

added Makefile, installation details in README

use parameter expansion, turn off debug mode to prevent data leak, ad…

…d a README

don't accept invalid input in argparse

fix password leak, changed help menu, changed argparse menu

copyright added, internal variable name changed