Revert minimum target version for macOS builds (#120)

Author: a5ehren

.github/workflows/ci.yaml

@@ -59,13 +59,13 @@ jobs:
           package-cache-key: ${{ hashFiles('**/xmake.lua', '!win-*/xmake.lua') }}
 
       - name: Configure (arm64)
-        run: xmake f -p macosx -a "arm64" -m release -y --target_minver=15.4
+        run: xmake f -p macosx -a "arm64" -m release -y --target_minver=13.5
 
       - name: Build (arm64)
         run: xmake -y
 
       - name: Configure (x86)
-        run: xmake f -p macosx -a "x86_64" -m release -y --target_minver=15.4
+        run: xmake f -p macosx -a "x86_64" -m release -y --target_minver=13.5
 
       - name: Build (x86)
         run: xmake -y