fwd.hpp : remove test for proxsuite version (since we use 0.10.0 minimum now)

Author: ManifoldFR

include/aligator/fwd.hpp

@@ -31,12 +31,7 @@ namespace aligator {
 
 // NOLINTBEGIN(misc-unused-using-decls)
 
-#if PROXSUITE_NLP_VERSION_AT_LEAST(0, 9, 0)
 using proxsuite::nlp::ConstraintSetTpl;
-#else
-template <typename T>
-using ConstraintSetTpl = proxsuite::nlp::ConstraintSetBase<T>;
-#endif
 using proxsuite::nlp::ManifoldAbstractTpl;
 // Use the math_types template from proxsuite-nlp.
 using proxsuite::nlp::VerboseLevel;