v0.13.1 - "Owned by me and not by thee"

This release fixes a bug in the provided Debian package.

The packages of 0.13.0 and earlier versions were not built with the fakeroot
utility, which caused the installed package files (/usr/bin/vaultenv and
/etc/secrets.d/) to be owned by the local user with uid 1000 instead of by root.
We've now adjusted the build script to correctly use fakeroot, the package will
also automatically correct this issue by changing the owner and mode of
/usr/bin/vaultenv and /etc/secrets.d when upgrading from an earlier version.

There are no changes to the code of the Vaultenv binary, except for an increase in
the version number.