updated crate stable version to 0.50.6

[chaudum]

No description provided.

[tianon]

LGTM (crate/docker-crate@afe4de8...46cbc25)

Build test of #1051; 0882938 (crate):

$ url="https://raw.githubusercontent.com/docker-library/official-images/08829380baaf922ee6874b603e7fbfde9b97d8ea/library/crate"
$ bashbrew build "$url"
Fetching crate (git://github.com/crate/docker-crate) ...
Processing crate:latest ...
Processing crate:0.49 ...
Processing crate:0.49.6 ...
Processing crate:0.50 ...
Processing crate:0.50.6 ...
$ bashbrew list --uniq "$url" | xargs test/run.sh
testing crate:latest
    'utc' [1/4]...passed
    'cve-2014--shellshock' [2/4]...passed
    'no-hard-coded-passwords' [3/4]...passed
    'override-cmd' [4/4]...passed
testing crate:0.49
    'utc' [1/4]...passed
    'cve-2014--shellshock' [2/4]...passed
    'no-hard-coded-passwords' [3/4]...passed
    'override-cmd' [4/4]...passed

[yosifkit]

LGTM