feat: Add macOS aarch64 build + support older MacOSX 10.7

Add an aarch64-apple-darwin (Apple Silicon) build target to the CI
matrix alongside the existing x86_64-apple-darwin target, so releases
include binaries for both Intel and Apple Silicon Macs. The x86_64
build is cross-compiled on the arm64 runner since macos-latest now
uses Apple Silicon hardware.

Set MACOSX_DEPLOYMENT_TARGET=10.7 for macOS builds so binaries only
depend on system features present in OS X 10.7 and older, maximizing
compatibility.

Update _release.yml to download and publish both macOS artifacts with
checksums.

Fixes #240

Prompts:
- [update macOS ci image · Issue #240 · timabell/gitopolis](#240)
- hang on, don't we need to provide for both arch's now there are two cpu arch's on different age macs?
- On macOS, we can set MACOSX_DEPLOYMENT_TARGET to 10.7 to only depend on system features present in versions 10.7 and older. ~ https://rust-cli.github.io/book/tutorial/packaging.html#building-binary-releases-on-ci
- commit

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: timabell

.github/workflows/_ci.yml

@@ -68,6 +68,10 @@ jobs:
           target: x86_64-apple-darwin
           artifact_name: gitopolis-macos-x86_64
           binary_name: gitopolis
+        - os: macos-latest
+          target: aarch64-apple-darwin
+          artifact_name: gitopolis-macos-aarch64
+          binary_name: gitopolis
     runs-on: ${{ matrix.os }}
     steps:
     - uses: actions/checkout@v6
@@ -125,6 +129,9 @@ jobs:
         VERSION="${VERSION#v}"
         sed -i '' "s/0\\.0\\.0-git/$VERSION/" Cargo.toml
         sed -i '' "s/0\\.0\\.0-git/$VERSION/" Cargo.lock
+    - name: Set macOS deployment target
+      if: runner.os == 'macOS'
+      run: echo "MACOSX_DEPLOYMENT_TARGET=10.7" >> $GITHUB_ENV
     - name: Build
       run: cargo build --target ${{ matrix.target }} --release
     - name: Test

.github/workflows/_release.yml

@@ -39,14 +39,19 @@ jobs:
       with:
         name: gitopolis-windows-x86_64
 
-    - name: Download macOS Build
+    - name: Download macOS x86_64 Build
       uses: actions/download-artifact@v8
       with:
         name: gitopolis-macos-x86_64
 
+    - name: Download macOS aarch64 Build
+      uses: actions/download-artifact@v8
+      with:
+        name: gitopolis-macos-aarch64
+
     - name: Generate SHA256 Checksums
       run: |
-        sha256sum gitopolis-linux-x86_64.tar.gz gitopolis-windows-x86_64.zip gitopolis-macos-x86_64.tar.gz > SHA256SUMS.txt
+        sha256sum gitopolis-linux-x86_64.tar.gz gitopolis-windows-x86_64.zip gitopolis-macos-x86_64.tar.gz gitopolis-macos-aarch64.tar.gz > SHA256SUMS.txt
 
     - name: Create Release
       uses: softprops/action-gh-release@v2
@@ -58,6 +63,7 @@ jobs:
           gitopolis-linux-x86_64.tar.gz
           gitopolis-windows-x86_64.zip
           gitopolis-macos-x86_64.tar.gz
+          gitopolis-macos-aarch64.tar.gz
           SHA256SUMS.txt
 
     - name: Update Version for crates.io