Attempt to add macos arm build to the CI workflow.

Adding macos arm to the set of GitHub runners and
supported binary distributions. This currently
fails on GitHub due to limited runner resources
that result in "Cancelled after 360m". It is not
an issue with macos-arm64 per-se, as the tests for
this configuration on pass on the CircleCI runner.

Keeping the code that renames the arm64 artifacts
differently from the x86_64 artifacts for later
use (expect this issue to be resolved with
SimpleITK 3.0.0).

Author: zivy

.circleci/config.yml

@@ -41,7 +41,9 @@ jobs:
             R_VERSION="<< parameters.r-version >>"
             # Install rig, R Installation Manager (https://github.com/r-lib/rig) to control installed R version
             if [ "$RUNNER_OS" == "macos" ]; then
-              brew install --cask r-lib/rig/rig
+              # Install specific version of rig (0.8.0) directly from GitHub releases
+              curl -L https://github.com/r-lib/rig/releases/download/v0.8.0/rig-macos-latest.pkg -o /tmp/rig.pkg
+              sudo installer -pkg /tmp/rig.pkg -target /
               rig add $R_VERSION
               # on macOS the R package is installed into a MAJOR.MINOR directory
               # the PATCH is ignored (only one patch version supported) the

.github/workflows/main.yml

@@ -96,7 +96,13 @@ jobs:
         PKG_VERSION=$(Rscript -e "cat(read.dcf('DESCRIPTION', 'Version')[1])")
 
         if [[ "$RUNNER_OS" == "macOS" ]]; then
-          PKG_NAME="SimpleITK_${PKG_VERSION}_R${R_VERSION_SHORT}_macos-x86_64.tgz"
+          # Detect architecture: arm64 or x86_64
+          ARCH=$(uname -m)
+          if [[ "$ARCH" == "arm64" || "$ARCH" == "aarch64" ]]; then
+            PKG_NAME="SimpleITK_${PKG_VERSION}_R${R_VERSION_SHORT}_macos-arm64.tgz"
+          else
+            PKG_NAME="SimpleITK_${PKG_VERSION}_R${R_VERSION_SHORT}_macos-x86_64.tgz"
+          fi
         elif [[ "$RUNNER_OS" == "Linux" ]]; then
           PKG_NAME="SimpleITK_${PKG_VERSION}_R${R_VERSION_SHORT}_linux-x86_64.tar.gz"
         elif [[ "$RUNNER_OS" == "Windows" ]]; then