refactor!: use Finalizer to automatically free allocated memory for objects (#48)

BREAKING CHANGE: signature change for remote and repository callbacks during repository clone operation.

analysis_options.yaml

@@ -4,8 +4,6 @@ analyzer:
   language:
     strict-casts: true
     strict-raw-types: true
-  strong-mode:
-    implicit-casts: false
 
   exclude:
     - lib/src/bindings/libgit2_bindings.dart
@@ -35,15 +33,12 @@ linter:
     - directives_ordering
     - eol_at_end_of_file
     - join_return_with_assignment
-    - library_private_types_in_public_api
     - lines_longer_than_80_chars
     - literal_only_boolean_expressions
     - missing_whitespace_between_adjacent_strings
     - no_default_cases
     - noop_primitive_operations
-    - null_check_on_nullable_type_parameter
     - omit_local_variable_types
-    - one_member_abstracts
     - parameter_assignments
     - prefer_asserts_in_initializer_lists
     - prefer_asserts_with_message
@@ -70,3 +65,4 @@ linter:
     - use_raw_strings
     - use_setters_to_change_properties
     - use_string_buffers
+    - use_super_parameters