Update references to emscripten/emsdk

[rgaudin]

Within kiwix/overview#82, we looked at all repos for dependency on Docker Images that may migrate out of Docker Hub.

You use emscripten/emsdk:3.1.12 as your base image. emscripten is a Community Organization.

While this specific image shall remain available (unless emscripten decides to), it is possible that emscripten decides to push future images to a different registry (alternatives being to pay a subscription to Hub or get accepted in their OSS Program).

You should probably find out what will happen and adjust your scripts accordingly.

See kiwix/kiwix-js#980

[Jaifroid]

It seems Emscripten continues to use Docker Hub.

[rgaudin]

Yes, as noted in the issue, Docker Hub canceled their plan so a lot of threaten users eventually stayed. Not a problem at this stage.

[Jaifroid]

OK, so for now I'll close. Many thanks.