avoid drift from scheduler environment

pixi.toml

@@ -56,12 +56,12 @@ xgboost = ">=1.0, <1.8"
 dask = "2023.11.0.*"
 cloudpickle = "3.0.0.*"
 
-# coffea-casa precautions
+# coffea-casa precautions: keep the drift small from scheduler
 pandas = ">=2.1.2, <2.2.4"
-lz4 = ">=4.3.2"
-msgpack-python = ">=1.0.6"
-toolz = ">=0.12.0"
-tornado = ">=6.3.3"
+lz4 = ">=4.3.2, <4.3.4"
+msgpack-python = ">=1.0.6, <1.1.1"
+toolz = ">=0.12.0, <1.0.1"
+tornado = ">=6.3.3, <6.4.2"
 
 # Debug to see if _exact_ scheduler environment replication is required
 # lz4 = "4.3.2.*"