upgrade to Isabelle2021-1

Citadelle/examples/archive/uml_ocl/Isabelle_Finite_Set.thy

...le/examples/archive/uml_ocl/OCL_lib_Gogolla_challenge.thy

...mples/archive/uml_ocl/OCL_lib_Gogolla_challenge_naive.thy

Citadelle/src/collection_types/UML_Bag.thy

Citadelle/src/collection_types/UML_Set.thy

Citadelle/src/compiler/Generator_dynamic_sequential.thy

...e/src/compiler_citadelle/Generator_dynamic_concurrent.thy

...c/compiler_citadelle/Generator_dynamic_export_testing.thy

...elle/src/compiler_generic/meta_isabelle/Meta_Isabelle.thy

...ic/toy_example/embedding/Generator_dynamic_sequential.thy

Citadelle/src/compiler_misc/Aux_text.thy

Citadelle/src/compiler_misc/meta/Printer_init.thy

Citadelle/src/uml_main/UML_PropertyProfiles.thy

Citadelle/src/uml_main/UML_State.thy