Update CONTRIBUTING for new linux dependencies
Update CONTRIBUTING for new linux dependencies

* python3-dev for linking against python in qrenderdoc
* bison, autoconf, automake and libpcre3-dev for building the custom
  SWIG used to generate bindings

Velro/renderdoc,googlestadia/renderdoc,baldurk/renderdoc,Yours3lf/renderdoc,Yours3lf/renderdoc,Yours3lf/renderdoc,Yours3lf/renderdoc,Yours3lf/renderdoc,baldurk/renderdoc,TurtleRockStudios/renderdoc_public,Lssikkes/renderdoc,googlestadia/renderdoc,Lssikkes/renderdoc,michaelrgb/renderdoc,etnlGD/renderdoc,michaelrgb/renderdoc,Lssikkes/renderdoc,Zorro666/renderdoc,TurtleRockStudios/renderdoc_public,baldurk/renderdoc,TurtleRockStudios/renderdoc_public,michaelrgb/renderdoc,victor-moya/renderdoc,Zorro666/renderdoc,Lssikkes/renderdoc,googlestadia/renderdoc,etnlGD/renderdoc,Zorro666/renderdoc,cgmb/renderdoc,cgmb/renderdoc,Zorro666/renderdoc,TurtleRockStudios/renderdoc_public,etnlGD/renderdoc,victor-moya/renderdoc,michaelrgb/renderdoc,michaelrgb/renderdoc,victor-moya/renderdoc,Velro/renderdoc,etnlGD/renderdoc,baldurk/renderdoc,Zorro666/renderdoc,TurtleRockStudios/renderdoc_public,baldurk/renderdoc,cgmb/renderdoc,googlestadia/renderdoc,Lssikkes/renderdoc,TurtleRockStudios/renderdoc_public,Lssikkes/renderdoc,Yours3lf/renderdoc,Velro/renderdoc,cgmb/renderdoc,victor-moya/renderdoc,Velro/renderdoc,cgmb/renderdoc,etnlGD/renderdoc,googlestadia/renderdoc,etnlGD/renderdoc,Velro/renderdoc,victor-moya/renderdoc,baldurk/renderdoc,victor-moya/renderdoc,Zorro666/renderdoc,googlestadia/renderdoc,Velro/renderdoc