Fix FreeBSD development dependencies
Fix FreeBSD development dependencies

- installing packages requires sudo
- imagemagick package was not found, corrected with imagemagick6
  (eventually we may want imagemagick7 but this is consistent with
  stable releases on other distros for now)

Co-authored-by: Yasuo Honda <815806a5fcba2cb411d0f70b662adf0091c5dee5@gmail.com>

esparta/rails,Erol/rails,georgeclaghorn/rails,BlakeWilliams/rails,yahonda/rails,kmcphillips/rails,Erol/rails,esparta/rails,yawboakye/rails,yahonda/rails,yahonda/rails,BlakeWilliams/rails,BlakeWilliams/rails,georgeclaghorn/rails,yawboakye/rails,georgeclaghorn/rails,Erol/rails,rails/rails,rails/rails,yawboakye/rails,yahonda/rails,georgeclaghorn/rails,BlakeWilliams/rails,kmcphillips/rails,MSP-Greg/rails,MSP-Greg/rails,rails/rails,kmcphillips/rails,esparta/rails,kmcphillips/rails,rails/rails,esparta/rails,Erol/rails,yawboakye/rails,MSP-Greg/rails,MSP-Greg/rails