CI runner tweaks (#464)

* Avoid testing Julia 1.6 on Windows

* Test against Apple silicon

* Add CodeCov token to avoid rate limiting

.github/workflows/CI.yml

@@ -34,19 +34,40 @@ jobs:
           - "1.6"  # LTS / Oldest supported version
           - "1"    # Latest release
           - nightly
+        # https://github.com/actions/runner-images#available-images
         os:
           - ubuntu-latest
-          - macOS-latest
+          - macos-14  # Apple silicon
           - windows-latest
         arch:
           - x64
           - x86
+          - aarch64
         exclude:
           # Test 32-bit only on Linux
-          - os: macOS-latest
+          - os: macos-14
             arch: x86
           - os: windows-latest
             arch: x86
+          # Test ARM64 only on macOS
+          - os: ubuntu-latest
+            arch: aarch64
+          - os: windows-latest
+            arch: aarch64
+          # Prefer testing against Apple Silicon
+          - os: macos-14
+            arch: x64
+          - version: "1.6"
+            os: macos-14
+            arch: aarch64
+          # Disable Windows tests on Julia 1.6 as it's particularly slow
+          - version: "1.6"
+            os: windows-latest
+        include:
+          # Apple silicon isn't supported by Julia 1.6
+          - version: "1.6"
+            os: macos-13  # Intel
+            arch: x64
     steps:
       - uses: actions/checkout@v4
       - uses: julia-actions/setup-julia@v2
@@ -60,6 +81,7 @@ jobs:
       - uses: codecov/codecov-action@v4
         with:
           files: lcov.info
+          token: ${{ secrets.CODECOV_TOKEN }}
 
   # https://pkgdocs.julialang.org/v1/creating-packages/#Transition-from-normal-dependency-to-extension
   weakdeps: