Clojure backward compatibility

[jsmassa]

Describe the feature you would like to request

Compatibility of datahike with earlier versions of clojure (and clojurescript).

Describe the solution you would like

Adding tests using earlier versions of clojure, for example by adding a test config for kaocha.

Describe alternatives you've considered

Only have datahike compatible with the most recent version as it is right now.

This restricts the use of datahike though to projects where using the latest version can be easily achieved.

For example, we had problems reported after PR #601 had been merged into main because abs had just recently been included into the core project.