feat: make this library dart 3 compatible

Author: close2

lib/csv_to_list_converter.dart

@@ -178,7 +178,7 @@ CsvParser? _buildNewParserWithSettings(
 }
 
 /// The input sink for a chunked csv-string to list conversion.
-class CsvToListSink extends ChunkedConversionSink<String> {
+class CsvToListSink implements ChunkedConversionSink<String> {
   /// Rows converted to Lists are added to this sink.
   final Sink<List> _outSink;
 

lib/list_to_csv_converter.dart

@@ -278,7 +278,7 @@ class ListToCsvConverter extends StreamTransformerBase<List, String>
 ///
 /// A single row represented by a [List] may be [add]ed an
 /// the conversion is added to the output sink.
-class List2CsvSink extends ChunkedConversionSink<List<List>> {
+class List2CsvSink implements ChunkedConversionSink<List<List>> {
   /// The List2CsvConverter which has the configurations (fieldDelimiter,
   /// textDel., eol)
   final ListToCsvConverter _converter;

pubspec.yaml

@@ -8,7 +8,7 @@ homepage: https://github.com/close2/csv
 documentation: https://github.com/close2/csv
 
 environment:
-  sdk: '>=2.12.0 <3.0.0'
+  sdk: '>=2.12.0 <4.0.0'
 
 dev_dependencies:
   test: ^1.16.8

test/csv_to_list_test.dart

@@ -516,7 +516,8 @@ void main_converter() {
           csvSingleRowComma,
           shouldParseNumbers: true,
         );
-      }, throwsA(isA<TypeError>()));
+      }, anyOf([throwsA(isA<TypeError>()), throwsA(isA<AssertionError>())]));
+      // dart 2 throws an `AssertionError`, dart 3 a `TypeError`
     });
     test('to return dynamic csv', () {
       expect(