Work around APT resolver weirdness

For some reason apt is now uninstalling the git-buildpackage and devscripts packages when trying to install the libconfig-model-dpkg-perl package:

$ apt install libconfig-model-dpkg-perl
...
The following packages will be REMOVED:
  devscripts git-buildpackage
The following NEW packages will be installed:
  fuse gnupg2 ...

To work around that, explicitly tell it that gnupg2 can be installed.

In order to prevent that from happening again, pass --no-remove to apt to make it fail explicitly rather than more or less silently dropping stuff.