github actions: use macos-latest (#1171)

macos-11 was deprecated and removed:

> The macos-11 label has been deprecated and will no longer be available after 28 June 2024.

We can just use macos-latest instead.

.github/workflows/release.yml

@@ -64,7 +64,7 @@ jobs:
     name: Build Universal Darwin
     env:
       HAS_SIGNING_CREDS: ${{ secrets.AC_USERNAME != '' }}
-    runs-on: macos-11
+    runs-on: macos-latest
     steps:
       - uses: actions/checkout@v4
 

.github/workflows/test.yml

@@ -72,7 +72,7 @@ jobs:
     runs-on: ${{ matrix.os }}
     strategy:
       matrix:
-        os: [windows-latest, macos-11]
+        os: [windows-latest, macos-latest]
     steps:
 
     - uses: actions/checkout@v4