ci(cuda): use the specified version for win and ubuntu

Author: pplmx

template/cuda/{{cookiecutter.project_slug}}/.github/workflows/ci.yml

@@ -11,8 +11,8 @@ jobs:
         strategy:
             matrix:
                 os:
-                    - ubuntu-latest
-                    - windows-latest
+                    - ubuntu-20.04
+                    - windows-2019
         name: {{ "${{ matrix.os }}" }}
         runs-on: {{ "${{ matrix.os }}" }}
         steps: