Update CI to use macOS 12

Author: smheidrich

.github/workflows/build.yml

@@ -21,7 +21,7 @@ jobs:
     runs-on: ${{ matrix.os }}
     strategy:
       matrix:
-        os: [ubuntu-20.04, windows-2019, macos-11]
+        os: [ubuntu-20.04, windows-2019, macos-12]
         cibw-build-prefix: ['*']
         include:
           - os: ubuntu-20.04

.github/workflows/test.yml

@@ -18,14 +18,14 @@ jobs:
     strategy:
       matrix:
         python-version: ["3.7"]
-        os: [ubuntu-20.04, windows-2019, macos-11]
+        os: [ubuntu-20.04, windows-2019, macos-12]
         include:
           # set OS-specific cache paths
           - os: ubuntu-20.04
             path: ~/.cache/pip
           - os: windows-2019
             path: ~\AppData\Local\pip\Cache
-          - os: macos-11
+          - os: macos-12
             path: ~/Library/Caches/pip
           # more combinations:
           - os: ubuntu-20.04