remove vendor prefixes from flexboxgrid.scss
remove vendor prefixes from flexboxgrid.scss

autoprefixer takes care of these for us. so it's
code we don't need, less to maintain.

But if you want to just leave it as-is so it's
easier to diff against the original that's fine
too. I'll abandon this.

FYI, the regex I used was .*-(ms|webkit|moz).*\n

test plan:
the outputted css should be exactly the same as
what it used to be.

Change-Id: I3178dd220f5f1bc67c579298ad730c6b1a8b9a95
Reviewed-on: https://gerrit.instructure.com/40622
Tested-by: Jenkins <d95b56ce41a2e1ac4cecdd398defd7414407cc08@instructure.com>
Reviewed-by: Chris Hart <b82b40b84a2f06957ec9caf1768340bd6b929cc4@instructure.com>
Product-Review: Ryan Shaw <ea3cd978650417470535f3a4725b6b5042a6ab59@instructure.com>
QA-Review: Ryan Shaw <ea3cd978650417470535f3a4725b6b5042a6ab59@instructure.com>

grahamb/canvas-lms,venturehive/canvas-lms,dgynn/canvas-lms,ShreniiNepal/shrenii_lmp,HotChalk/canvas-lms,matematikk-mooc/canvas-lms,HotChalk/canvas-lms,SwinburneOnline/canvas-lms,snehakachroo1/LSI_replica,snehakachroo1/LSI_replica,AndranikMarkosyan/lms,fronteerio/canvas-lms,leftplusrightllc/canvas-lms,dgynn/canvas-lms,dgynn/canvas-lms,tgroshon/canvas-lms,Jyaasa/canvas-lms,dgynn/canvas-lms,instructure/canvas-lms,kyroskoh/canvas-lms,sdeleon28/canvas-lms,va7map/canvas-lms,ShreniiNepal/shrenii_lmp,matematikk-mooc/canvas-lms,samuels410/greatlakes-lms,leftplusrightllc/canvas-lms,jay3126/canvas-lms,wrdsb/canvas-lms,gbleydon/canvas-lms,grahamb/canvas-lms,sdeleon28/canvas-lms,sfu/canvas-lms,fronteerio/canvas-lms,wrdsb/canvas-lms,skmezanul/canvas-lms,roxolan/canvas-lms,AndranikMarkosyan/lms,skmezanul/canvas-lms,Rvor/canvas-lms,Rvor/canvas-lms,whalejasmine/canvas-lms,whalejasmine/canvas-lms,fronteerio/canvas-lms,shidao-fm/canvas-lms,grahamb/canvas-lms,narigone/canvas,juoni/canvas-lms,matematikk-mooc/canvas-lms,roxolan/canvas-lms,grahamb/canvas-lms,snehakachroo1/LSI_replica,greyhwndz/canvas-lms,va7map/canvas-lms,SwinburneOnline/canvas-lms,Jyaasa/canvas-lms,shidao-fm/canvas-lms,kyroskoh/canvas-lms,wrdsb/canvas-lms,narigone/canvas,utkarshx/canvas-lms,tgroshon/canvas-lms,redconfetti/canvas-lms,eCNAP/CANVAS,eCNAP/CANVAS,skmezanul/canvas-lms,utkarshx/canvas-lms,AndranikMarkosyan/lms,jay3126/canvas-lms,venturehive/canvas-lms,instructure/canvas-lms,eCNAP/CANVAS,gbleydon/canvas-lms,instructure/canvas-lms,djbender/canvas-lms,va7map/canvas-lms,kyroskoh/canvas-lms,juoni/canvas-lms,wye0220/shindig-canvas,Rvor/canvas-lms,leftplusrightllc/canvas-lms,snehakachroo1/LSI_replica,jay3126/canvas-lms,Jyaasa/canvas-lms,va7map/canvas-lms,tgroshon/canvas-lms,djbender/canvas-lms,sfu/canvas-lms,antoniuslin/canvas-lms,Jyaasa/canvas-lms,shidao-fm/canvas-lms,sfu/canvas-lms,jay3126/canvas-lms,wrdsb/canvas-lms,instructure/canvas-lms,roxolan/canvas-lms,instructure/canvas-lms,ShreniiNepal/shrenii_lmp,roxolan/canvas-lms,redconfetti/canvas-lms,wye0220/shindig-canvas,juoni/canvas-lms,narigone/canvas,sfu/canvas-lms,tgroshon/canvas-lms,sfu/canvas-lms,wye0220/shindig-canvas,samuels410/greatlakes-lms,greyhwndz/canvas-lms,instructure/canvas-lms,Rvor/canvas-lms,SwinburneOnline/canvas-lms,whalejasmine/canvas-lms,sdeleon28/canvas-lms,djbender/canvas-lms,antoniuslin/canvas-lms,greyhwndz/canvas-lms,eCNAP/CANVAS,efrj/canvas-lms,greyhwndz/canvas-lms,shidao-fm/canvas-lms,AndranikMarkosyan/lms,instructure/canvas-lms,grahamb/canvas-lms,efrj/canvas-lms,redconfetti/canvas-lms,fronteerio/canvas-lms,matematikk-mooc/canvas-lms,sdeleon28/canvas-lms,efrj/canvas-lms,venturehive/canvas-lms,kyroskoh/canvas-lms,redconfetti/canvas-lms,SwinburneOnline/canvas-lms,HotChalk/canvas-lms,leftplusrightllc/canvas-lms,HotChalk/canvas-lms,ShreniiNepal/shrenii_lmp,whalejasmine/canvas-lms,antoniuslin/canvas-lms,samuels410/greatlakes-lms,narigone/canvas,utkarshx/canvas-lms,juoni/canvas-lms,sfu/canvas-lms,gbleydon/canvas-lms,samuels410/greatlakes-lms,efrj/canvas-lms,djbender/canvas-lms,utkarshx/canvas-lms,venturehive/canvas-lms,antoniuslin/canvas-lms,sfu/canvas-lms,skmezanul/canvas-lms