Metrics-layer

What's Changed
* add joinable function to `Project` by pblankley in https://github.com/Zenlytic/metrics_layer/pull/195


**Full Changelog**: https://github.com/Zenlytic/metrics_layer/compare/v0.12.15...v0.12.16

What's Changed
* Fix bug in postgres symm aggregate and in merged results with a having filter not in the select clause by pblankley in https://github.com/Zenlytic/metrics_layer/pull/194


**Full Changelog**: https://github.com/Zenlytic/metrics_layer/compare/v0.12.14...v0.12.15

What's Changed
* use coalesce instead of ifull for wider version support by pblankley in https://github.com/Zenlytic/metrics_layer/pull/193


**Full Changelog**: https://github.com/Zenlytic/metrics_layer/compare/v0.12.13...v0.12.14

What's Changed
* Feature/arbitrary merged results by pblankley in https://github.com/Zenlytic/metrics_layer/pull/192


**Full Changelog**: https://github.com/Zenlytic/metrics_layer/compare/v0.12.12...v0.12.13

What's Changed
* Feature/fix count non additive metrics by pblankley in https://github.com/Zenlytic/metrics_layer/pull/191
* Fix bug with bigquery week date trunc when applied as a filter
* Fix bug with multi hop symmetric aggregate uncaught error


**Full Changelog**: https://github.com/Zenlytic/metrics_layer/compare/v0.12.11...v0.12.12

What's Changed
* Use context manager to replace fields by ColeFrench in https://github.com/Zenlytic/metrics_layer/pull/190

New Contributors
* ColeFrench made their first contribution in https://github.com/Zenlytic/metrics_layer/pull/190

**Full Changelog**: https://github.com/Zenlytic/metrics_layer/compare/v0.12.10...v0.12.11