Fix FlexUnits version format in Project.toml

Made a correction to the argument formats

Author: Deduction42

lib/DiffEqBase/Project.toml

@@ -86,7 +86,7 @@ Enzyme = "0.13.100"
 FastBroadcast = "1.3"
 FastClosures = "0.3.2"
 FastPower = "1.1.2"
-FlexUnits = "0.5", "0.6"
+FlexUnits = "0.5, 0.6"
 ForwardDiff = "0.10, 1"
 FunctionWrappers = "1.1.3"
 FunctionWrappersWrappers = "1"