add: color invariant regions to match the live build

> Genotypes with no observed mutations can only be coloured with the optional _root-sequence.json sidecar file.
> Without this we have no way of knowing what the base is at this position.

#9

Author: j23414

Snakefile

@@ -203,6 +203,7 @@ rule export:
             --colors {input.colors} \
             --lat-longs {input.lat_longs} \
             --auspice-config {input.auspice_config} \
+            --include-root-sequence \
             --output {output.auspice_json}
         """