antlr4-python3-runtime dependency makes statsforecast incompatible with other packages

[shchur]

Problem

The current conda-forge recipe for statsforecast includes the dependency on antlr4-python3-runtime>=4.11. This prevents installation of statsforecast via conda alongside packages relying on older antlr4 versions (e.g., omegaconf requires antlr4-python3-runtime==4.9.3).

https://github.com/conda-forge/statsforecast-feedstock/blob/main/recipe/meta.yaml#L31-L34

This, for example, makes it impossible to install statsforecast>=1.5.0 alongside pytorch-lightning[extra] in a single environment since pytorch-lightning relies on omegaconf (https://github.com/Lightning-AI/pytorch-lightning/blob/master/requirements/pytorch/extra.txt#L6).

This problem also make it impossible to install statsforecast>=1.5.0 alongside autogluon that similarly depends on omegaconf.

Note that installation via pip works and this problem only affects the conda install.

Potential solution

This problem can be resolved by increasing the fugue lower bound to fugue>=0.9.0, which will make antr4 an optional dependency (fugue-project/fugue#509).