CI: add macOS-latest for make-check and macos-installer action

macOS-latest (macos-12) is available for github action and as of now we are only
using macOS-11 so better to add it also.

- https://github.com/actions/runner-images/blob/main/images/macos/macos-12-Readme.md

.github/workflows/macos-installer.yml

@@ -18,6 +18,7 @@ jobs:
       fail-fast: false
       matrix:
         os:
+          - macOS-latest
           - macOS-11
         go:
           - 1.17

.github/workflows/make-check.yml

@@ -13,6 +13,7 @@ jobs:
       matrix:
         os:
           - macOS-11
+          - macOS-latest
           - ubuntu-latest
           - ubuntu-20.04
         go: