Webmin version mismatch

[biggnou]

Hi,

As per http://download.webmin.com/download/repository/dists/sarge/contrib/binary-amd64/Packages, the Webmin version in the repo is 1.962. But the Dockerfile pins it at 1.941.

Just changing the Dockerfile refence should work.

Alex.

[biggnou]

Created PR #106.