Add version info when building CI/CD for apple platforms

docs/README-macos.md

@@ -13,7 +13,7 @@ To build SDL using the command line, use the CMake build script:
 ```bash
 mkdir build
 cd build
-cmake ..
+cmake .. -DCMAKE_OSX_DEPLOYMENT_TARGET=10.11
 cmake --build .
 sudo cmake --install .
 ```
@@ -25,7 +25,7 @@ You can also build SDL as a Universal library (a single binary for both
 ```bash
 mkdir build
 cd build
-cmake .. "-DCMAKE_OSX_ARCHITECTURES=arm64;x86_64"
+cmake .. "-DCMAKE_OSX_ARCHITECTURES=arm64;x86_64" -DCMAKE_OSX_DEPLOYMENT_TARGET=10.11
 cmake --build .
 sudo cmake --install .
 ```