Use another docker images for osx builds.
Use another docker images for osx builds.

The updated image is using SDK 10.14 (instead of 10.8) and is running
Ubuntu 18.04. Unfortunately, the dmd version provided by 18.04 fails to
build the dlang interface using dub (see
https://github.com/dlang/dub/issues/1474 for more details). Thus, dlang
has been disabled until a fix is published.

msteinbeck/tinyspline,msteinbeck/tinyspline,retuxx/tinyspline,msteinbeck/tinyspline,retuxx/tinyspline,retuxx/tinyspline,msteinbeck/tinyspline,msteinbeck/tinyspline,msteinbeck/tinyspline,msteinbeck/tinyspline,msteinbeck/tinyspline