remove: DiffResults dependency

Author: franckgaga

Project.toml

@@ -5,7 +5,6 @@ version = "1.1.4"
 
 [deps]
 ControlSystemsBase = "aaaaaaaa-a6ca-5380-bf3e-84a91bcd477e"
-DiffResults = "163ba53b-c6d8-5494-b064-1a9d43ac40c5"
 ForwardDiff = "f6369f11-7733-5829-9624-2563aa707210"
 Ipopt = "b6b21f68-93f8-5de0-b562-5493be1d77c9"
 JuMP = "4076af6c-e467-56ae-b986-b466b2749572"
@@ -19,7 +18,6 @@ RecipesBase = "3cdcf5f2-1ef4-517c-9805-6587b60abb01"
 
 [compat]
 ControlSystemsBase = "1.9"
-DiffResults = "1.1.0"
 ForwardDiff = "0.10"
 Ipopt = "1"
 JuMP = "1.21"