### Context [PangoLEARN has been deprecated](https://github.com/cov-lineages/pangoLEARN). ### Description We should remove [PangoLEARN from the image](https://github.com/nextstrain/docker-base/blob/1b0d1998c8cb03cbd0b5eb630fcd86fdfb247c99/Dockerfile#L175-L181), since it is no longer supported.
Context
PangoLEARN has been deprecated.
Description
We should remove PangoLEARN from the image, since it is no longer supported.