Upgrade the Emscripten Ubuntu image to 20.04

Upgrade the underlying operating system for a newer CMake version which is necessary to compile Xerces-C++.

assigned to @imeyer

enabled an automatic merge when the pipeline for bf8e9f9a succeeds

added 1 commit

• 727bcbbf - Upgrade the Emscripten Ubuntu image to 20.04

Compare with previous version

enabled an automatic merge when the pipeline for 727bcbbf succeeds

mentioned in commit a4140968

merged