Fix entering nix sandboxes

Executing setcap wrapper was broken.

podman support

also upgrade some dependencies

bump version in cargo.lock

Merge pull request Mic92#30 from Mic92/clippy

fix clippy warnings

ci/publish: fix executable name

- create /var/lib/cntr before entering the container

bump version to 1.2.0

- attach container by matching command line arguments
- support environments without CAP_SYS_CHROOT
- support docker-pid for resolving container pids

bump version to 1.1.2

- Makes cntr compatible with older kernels. 3.13 have been tested.
- Fixes apparmor support that accidently broke by selinux support.

cargo.toml: add license

rework documentation