Merge pull request #124 from JuliaSymbolics/compathelper/new_version/2020-08-18-18-42-05-845-693072483

CompatHelper: bump compat for "DataStructures" to "0.18"

Author: shashi

Project.toml

@@ -14,7 +14,7 @@ TimerOutputs = "a759f4b9-e2f1-59dc-863e-4aeb61b1ea8f"
 [compat]
 AbstractAlgebra = "0.9, 0.10"
 Combinatorics = "1.0"
-DataStructures = "0.17"
+DataStructures = "0.17, 0.18"
 NaNMath = "0.3"
 SpecialFunctions = "0.10"
 TimerOutputs = "0.5"