ci: Fix incorrect dart package version due to failing release (#1032)

Author: mtrezza

packages/dart/lib/src/base/parse_constants.dart

@@ -1,7 +1,7 @@
 part of '../../parse_server_sdk.dart';
 
 // Library
-const String keySdkVersion = '8.1.0';
+const String keySdkVersion = '8.0.0';
 const String keyLibraryName = 'Flutter Parse SDK';
 
 // End Points

packages/dart/pubspec.yaml

@@ -1,6 +1,6 @@
 name: parse_server_sdk
 description: The Dart SDK to connect to Parse Server. Build your apps faster with Parse Platform, the complete application stack.
-version: 8.1.0
+version: 8.0.0
 homepage: https://parseplatform.org
 repository: https://github.com/parse-community/Parse-SDK-Flutter
 issue_tracker: https://github.com/parse-community/Parse-SDK-Flutter/issues