Can't find db.fn/cas

[ashnur]

How to do compare-and-swap? I can't find it anywhere. Tried multiple ways and gives back Unknown operation

[typeetfunc]

@ashnur I add test for this case and export of db.fn/cas keyword. See tests:

1. JS API - https://github.com/typeetfunc/datascript-mori/blob/master/release-js/test/combineJsAndCljsApi.spec.js#L53
2. CLJS API - https://github.com/typeetfunc/datascript-mori/blob/master/release-js/test/onlyCljsApiUsage.spec.js#L132