Add fakeroot to Depends

dpkg-buildpackage needs the fakeroot, otherwise fails with:

| + dpkg-buildpackage -uc -us -nc -d -S -i -I --source-option=--unapply-patches
| dpkg-buildpackage: error: fakeroot not found, either install the fakeroot
| package, specify a command with the -r option, or run this as root
| Build step 'Execute shell' marked build as failure