fix compatibility with QGIS >= 3.13
([#94](https://github.com/BRGM/gml_application_schema_toolbox/issues/94))
- start using GitHub Actions for continuous integration and deployment
- bump development guidelines using black, flake8, isort and precommit
[#95](https://github.com/BRGM/gml_application_schema_toolbox/pull/95)
- add template for issues
[#97](https://github.com/BRGM/gml_application_schema_toolbox/pull/97)
- bump codebase to Python 3 only
[#98](https://github.com/BRGM/gml_application_schema_toolbox/pull/98)
- automate release workflow using qgis-plugin-ci
[#101](https://github.com/BRGM/gml_application_schema_toolbox/pull/101)