Build arm64-linux binaries in CI

[tueda]

This closes #619.

[coveralls]

coverage: 49.263% (-0.03%) from 49.29%
when pulling 41966e3 on tueda:ci-build-arm64-linux
into 5e4cef5 on vermaseren:master.

[tueda]

signed char → SBYTE. This clarifies the intention.

[tueda]

Moving from the ubuntu-20.04 image to ubuntu-22.04 image with this patch will fail to build binaries because of the same cache hash key for the different architectures. This PR will fix this build failure. A temporary workaround would be manually adding the architecture to the cache key:

-          version: 1.0
+          version: ${{ runner.arch }}-1.0

[jodavies]

That PR does not seem to have much activity, perhaps working around it locally is a good way to go for now.

[tueda]

Rebased and applied the workaround for cache-key conflicts.

[tueda]

Fixed and added a summary to see which files were generated.

[jodavies]

Looks good, ready to merge (also for 4.3)?

[tueda]

Sure, go ahead.