Remove deprecated linter rules (#132)

Author: yurii-prykhodko-solid

lib/analysis_options.yaml

@@ -95,7 +95,6 @@ linter:
   rules:
     - always_declare_return_types
     - always_put_required_named_parameters_first
-    - always_require_non_null_named_parameters
     - always_use_package_imports
     - annotate_overrides
     - avoid_bool_literals_in_conditional_expressions
@@ -121,7 +120,6 @@ linter:
     - avoid_relative_lib_imports
     - avoid_renaming_method_parameters
     - avoid_return_types_on_setters
-    - avoid_returning_null_for_future
     - avoid_returning_null_for_void
     - avoid_setters_without_getters
     - avoid_shadowing_type_parameters