Modernise, remove deps (bsm#93)

Merge pull request bsm#91 from jrobin42/master

Format ratio added

Merge pull request bsm#76 from ollevche/fix-typo

fix a typo in 7-12 Education Content Category

Merge pull request bsm#74 from ollevche/fix-typo

fix a typo in 3D Graphics Content Category

Merge pull request bsm#69 from EastResident/feature/video_duration_op…

…tional

Not validate "video.minduration" and "maxduration"

Merge pull request bsm#68 from bsm/feature/v3

Ready for v3

Fix build

Bump CI config

Merge pull request bsm#39 from emaraschio/master

bidrequest: Add new fields related to seats from 2.5 Spec

Merge pull request bsm#34 from marklr/master

Add support for stringified imp.secure attribute