ci -> macos-11

Author: heckj

.github/workflows/iostest.yml

@@ -18,10 +18,10 @@ jobs:
 
  build:
 
- runs-on: macos-latest
+ runs-on: macos-11
  env:
  # sets the version of Xcode to utilize within the VM for all steps
- DEVELOPER_DIR: /Applications/Xcode_12.4.app/Contents/Developer
+ # DEVELOPER_DIR: /Applications/Xcode_13.app/Contents/Developer
  steps:
  - uses: actions/checkout@v2