More buster

Author: altendky

.github/workflows/ci.yml

@@ -34,10 +34,10 @@ jobs:
               3.6: docker://python:3.6-buster
               3.7: docker://python:3.7-buster
               3.8: docker://python:3.8-buster
-              3.9: docker://python:3.9-rc-buster
-              pypy2.7: docker://pypy:2.7-jessie
-              pypy3.6: docker://pypy:3.6-stretch
-              pypy3.7: docker://pypy:3.7-stretch
+              3.9: docker://python:3.9-buster
+              pypy2.7: docker://pypy:2.7-buster
+              pypy3.6: docker://pypy:3.6-buster
+              pypy3.7: docker://pypy:3.7-buster
           - name: Windows
             runs-on: windows-latest
             python_platform: win32