fix tests for dart null safe version

Author: lohanidamodar

tests/SDKTest.php

@@ -52,14 +52,11 @@ class SDKTest extends TestCase
             'build' => [
                 'mkdir -p tests/sdks/dart/tests',
                 'cp tests/languages/dart/tests.dart tests/sdks/dart/tests/tests.dart',
-                'docker run --rm -v $(pwd):/app -w /app/tests/sdks/dart --env PUB_CACHE=vendor google/dart:2.7 pub get',
+                'docker run --rm -v $(pwd):/app -w /app/tests/sdks/dart --env PUB_CACHE=vendor google/dart:2.12 pub get',
             ],
             'envs' => [
-                // 'dart-2.6' => 'docker run --rm -v $(pwd):/app -w /app/tests/sdks/dart --env PUB_CACHE=vendor google/dart:2.6 pub run tests/tests.dart',
-                'dart-2.7' => 'docker run --rm -v $(pwd):/app -w /app/tests/sdks/dart --env PUB_CACHE=vendor google/dart:2.7 pub run tests/tests.dart',
-                'dart-2.8' => 'docker run --rm --tty -it -v $(pwd):/app -w /app/tests/sdks/dart --env PUB_CACHE=vendor google/dart:2.8 pub run tests/tests.dart',
-                'dart-2.10' => 'docker run --rm -v $(pwd):/app -w /app/tests/sdks/dart --env PUB_CACHE=vendor google/dart:2.10 dart pub run tests/tests.dart',
-                'dart-2.12-beta' => 'docker run --rm -v $(pwd):/app -w /app/tests/sdks/dart --env PUB_CACHE=vendor google/dart:2.12-beta dart pub run tests/tests.dart',
+                'dart-2.12' => 'docker run --rm -v $(pwd):/app -w /app/tests/sdks/dart --env PUB_CACHE=vendor google/dart:2.12 dart pub run tests/tests.dart',
+                'dart-2.13-dev' => 'docker run --rm -v $(pwd):/app -w /app/tests/sdks/dart --env PUB_CACHE=vendor google/dart:2.13-dev dart pub run tests/tests.dart',
             ],
             'supportRedirect' => true,
             'supportUpload' => true,