chore: move 2020.1 beta to ga image

.github/workflows/build-debug.yml

@@ -29,11 +29,11 @@ jobs:
     if: "!(contains(github.event.head_commit.message, '[skip ci]') || contains(github.event.head_commit.message, '[ci skip]')) && ((github.event_name == 'push' && github.repository_owner == 'Cysharp') || startsWith(github.event.pull_request.head.label, 'Cysharp:'))"
     strategy:
       matrix:
-        unity: ["2019.3.9f1", "2020.1.0b5"]
+        unity: ["2019.3.9f1", "2020.1.12f1"]
         include:
           - unity: 2019.3.9f1
             license: UNITY_2019_3
-          - unity: 2020.1.0b5
+          - unity: 2020.1.12f1
             license: UNITY_2020_1
     runs-on: ubuntu-latest
     container: