Downgrade apt cookbook for vagrant's chef compatibility.

According to the apt's read me versions 1.8.2 to 1.10.0 depend on specific
Chef > 10.16.4 APIs. I suppose that for version 2.0 (current) the dependency is even
tighter, so I was testing and found that 1.10 completes the provisioning procedure
correctly, despite of being running chef 10.14.2, so I'm locking it to that version
on the Berksfile.