CI: disable Windows build with old Flutter SDK.

Author: greenrobot-team

.github/workflows/dart.yml

@@ -98,8 +98,9 @@ jobs:
         include:
           - flutter-version: 3.3.3 # Flutter 2.9 and newer need Visual Studio 2022 to build desktop.
             os: windows-2022
-          - flutter-version: 2.5.0 # Flutter 2.8.1 and older need Visual Studio 2019 to build desktop.
-            os: windows-2019
+          # Currently, do not build with old Flutter version on Windows, versioning changes require Flutter 3.3+.
+          #- flutter-version: 2.5.0 # Flutter 2.8.1 and older need Visual Studio 2019 to build desktop.
+          #  os: windows-2019
     runs-on: ${{ matrix.os }}
     steps:
       - uses: actions/checkout@v2