Require Snakemake version <5.11
Require Snakemake version <5.11

This is a temporary workaround for requirement of `--cores` implemented in Snakemake version 5.11. For more information see here: https://github.com/snakemake/snakemake/issues/283.
nextstrain/augur,nextstrain/augur,blab/nextstrain-augur,nextstrain/augur