fix boolean flags

[nikoladze]

The command line arguments --complete, --purge and --stat have been configured in the original autojump implementation with action="store_true", compare e.g.

https://github.com/wting/autojump/blob/06e082c91805cb022900819b2e0881eeae780d58/bin/autojump#L120

To achieve the same here i added an ArgAction::SetTrue and changed app.contains_id to app.get_flag for these options. Now for me the fzf integration code snippet works again which makes use of the -s option and was broken with autojump-rs. For me autocompletion also seems to work now, so I think #213 should also be fixed by this PR.

[xen0n]

Not sure why the CI (specifically the i686-linux-android job) is failing, but the change should not be responsible for that; I'll have to process this later but I expect to merge this eventually. Thanks for the catch!