New `fuzz` profile is added
because cargo-bolero now requires it and uses
by default, while `--release` option is removed.
Instructions for running AFL are removed from the README
because it requires some system reconfiguration
and I did not test it this time.
Say in the README that cargo-bolero@0.8.0
should be installed as newer versions
do not work currently.
Update `mailparse` to 0.16.0
because this is what Delta Chat currently uses.
I also added fuzzer outputs to .gitignore