Pin docker-modem and dockerode to avoid regression

[kb2ma]

We are seeing a test failure in the "balena build" tests when dedupe dependencies on current master. The issue looks to be a regression in docker-modem, as described in the offending PR, which was incorporated into docker-modem v5.0.6.

This PR pins docker-modem on v5.0.5 and dockerode on v4.0.3. The latest dockerode release, v4.0.4, also depends on docker-modem v5.0.6.

Error:    Build failed.
expected [ [ 'platform', 'linux/amd64' ],
  [ 'buildargs', { BARG1: 'b1', barg2: 'B2' } ],
  [ 'cachefrom', 'my/img1' ],
  [ 'cachefrom', 'my/img2' ],
  [ 't', 'basic_main' ],
  [ 'labels', '' ] ] to have the same members as [ [ 't', 'basic_main' ],
  [ 'buildargs', { BARG1: 'b1', barg2: 'B2' } ],
  [ 'labels', '' ],
  [ 'platform', 'linux/amd64' ],
  [ 'cachefrom', [ 'my/img1', 'my/img2' ] ] ]