fix install-zig for mac

Signed-off-by: James Xin <[email protected]>

Author: jamesx-improving

.github/workflows/install-zig/action.yml

@@ -6,7 +6,9 @@ runs:
     - name: Install zig
       shell: bash
       run: |
-        if [[ `cat /etc/os-release | grep "Amazon Linux"` ]]; then
+        if [[ "$OSTYPE" == "darwin"* ]]; then
+            echo "macOS detected, pip3 already available"
+        elif [[ `cat /etc/os-release | grep "Amazon Linux"` ]]; then
             yum install -y python3-pip
         else
             sudo apt install -y python3-pip