CompatHelper: bump compat for MemPool to 0.4, (keep existing compat)

Author: CompatHelper Julia

Project.toml

@@ -27,7 +27,7 @@ Dagger = "0.8,0.9,0.10,0.11"
 DataValues = "0.4.12"
 Glob = "1"
 IndexedTables = "0.12.4,1"
-MemPool = "0.2,0.3"
+MemPool = "0.2,0.3, 0.4"
 Nullables = "0.0.8,1"
 OnlineStats = "1"
 OnlineStatsBase = "1"