Merge pull request harp-tech#47 from harp-tech/license-spdx

Replace license classifier with SPDX expression

Merge pull request harp-tech#44 from harp-tech/unified-io

Refactor IO API for consistency and symmetry

Merge pull request harp-tech#36 from harp-tech/gl-dev

Add CI pipeline and code coverage

Update schema submodule

Merge pull request harp-tech#7 from harp-tech/gl-dev

Prepare package metadata for first release