ci: try newer images

.github/workflows/ci.yml

diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index dcc61ec..74a614d 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -23,7 +23,7 @@
     strategy:
       fail-fast: false
       matrix:
-        runs-on: [ubuntu-latest, windows-latest, macos-latest]
+        runs-on: [ubuntu-latest, windows-2022, macos-11]
         python:
         - '2.7'
         - '3.5'