Change the default branch to main and fix test

This release fixes a test that checks the modern version of Solr.

n.b. this repository is slated to be archived in the near future; it's only used to set up Solr for local tests, which is much better achieved by using containers.

Migrate from Travis-CI to Github Actions and fix fetcher tests

Merge pull request #2 from trln/github-actions

GitHub actions

Look, a release

Previously versioned, but this one gets a tag. Should work with solr 7.x and 8.x.