CompatHelper: bump compat for DiffEqCallbacks to 4 and drop 2.3.6 (#331)

* CompatHelper: bump compat for DiffEqCallbacks to 4, (keep existing compat)

* Update Project.toml

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Co-authored-by: CompatHelper Julia <[email protected]>
Co-authored-by: Nathanael Bosch <[email protected]>

Author: 3 people

Project.toml

@@ -51,7 +51,7 @@ RecipesBaseExt = "RecipesBase"
 ArrayAllocators = "0.3"
 BlockArrays = "1"
 DiffEqBase = "6.122"
-DiffEqCallbacks = "2.36, 3"
+DiffEqCallbacks = "3, 4"
 DiffEqDevTools = "2"
 DocStringExtensions = "0.9"
 FastBroadcast = "0.2, 0.3"