Test with OpenMath.dev package as well

[olexandr-konovalov]

TODO: add additional test configurations to use OpenMath package clone from GitHub (https://github.com/gap-packages/openmath) instead of released version.

[olexandr-konovalov]

May also test with client/server from versions from the merged packages archive to check backwards compatibility. It should be possible that client and server have different versions.