Fix automatic ARM cross-compilation on github actions

[etr]

Is your feature request related to a problem? Please describe.
Many users often report building the library for ARM. This would prevent problems in the building system for these use-cases.

Describe why the feature or enhancement you are proposing fits the library.
Given the library is used quite a lot on embedded systems, this fits the use-case by delivering certainty of a successful build.

Describe the solution you'd like
Include a cross-compilation test-case in travis.

Describe alternatives you've considered
None

[LeSpocky]

Travis was removed with #222, but I guess the feature is still wanted, but for github actions now?

[etr]

yep. We still don't have a system to perform automated cross-compilation on ARM over the current CI tool (github-actions). Renamed the issue.