Pin conda 4.2.13 to work with conda-execute
Pin conda 4.2.13 to work with conda-execute

Right now `conda-execute` is not compatibility with `conda` 4.3. So
unfortunately we need to pin `conda` to a version `conda-execute` is
compatible with. Hopefully this pinning can be released once
`conda-execute` has been fixed.

conda-forge/conda-forge.github.io,conda-forge/conda-forge.github.io,conda-forge/conda-forge.github.io,conda-forge/conda-forge.github.io