Adding github actions for automated tests without an azure account.

[renemadsen]

Adding dependabot for easy testing of dependency updates.

I made the changes to allow contributers like my self to be able to see test results, without having to do a PR, since Github actions does not require an azure account and just runs with the changes a person does.

I added the dependabot, since we are using Pomelo.EntityFrameworkCore.MySql in a lot of projects and would like to have dependencies updated faster/easier. This can be done with letting dependabot run tests for new updates and the gab of breaking changes can be minimized by doing micro updates of dependencies.