Fix deprecation warning when building conda package
When building/releasing conda package, we get this deprecation warning:
```
/usr/share/miniconda/envs/build-datasets/bin/conda-build:11: DeprecationWarning: conda_build.cli.main_build.main is deprecated and will be removed in 4.0.0. Use `conda build` instead.
```

This PR fixes the deprecation warning by using `conda build` instead.