Runtime macOS - Deployment Setup

This should lay the foundation for deploying runtime changes to the public `rive-macos` repo and publishing SPM/CocoaPod named `RiveMacOS`.

### Files to look at:
- dev/**[mono.sh](1e3469e82c/dev/mono.sh)**
- .github/workflows/**[apply_changes_downstream.yaml](1e3469e82c/.github/workflows/apply_changes_downstream.yaml)**
- .github/actions/setup-downstream/**[action.yml](1e3469e82c/.github/actions/setup-downstream/action.yml)**
- packages/runtime_mac/.github/**
- packages/runtime_mac/scripts/**
- packages/runtime/skia/dependencies/**[make_skia_macos.sh](1e3469e82c/packages/runtime/skia/dependencies/make_skia_macos.sh)**

Diffs=
3039909c2 Update to using deployment workflow similar to ios

skia/dependencies/make_skia_macos.sh

@@ -0,0 +1,119 @@
+#!/bin/bash
+
+set -ex
+
+export MAKE_SKIA_FILE="$0"
+source ./get_skia2.sh
+source ./cache_helper.sh
+
+build_skia_macos(){
+    cd $SKIA_DIR_NAME
+
+    local SHARED_EXTRA_CFLAGS="\
+        \"-fno-rtti\",                                      \
+        \"-DSK_DISABLE_LEGACY_SHADERCONTEXT\",              \
+        \"-DSK_DISABLE_LOWP_RASTER_PIPELINE\",              \
+        \"-DSK_FORCE_RASTER_PIPELINE_BLITTER\",             \
+        \"-DSK_DISABLE_AAA\",                               \
+        \"-DSK_DISABLE_EFFECT_DESERIALIZATION\"             \
+    "
+
+    local SHARED_ARGS="\
+        is_official_build=true \
+        skia_use_gl=true \
+        skia_use_zlib=true \
+        skia_enable_gpu=true \
+        skia_enable_fontmgr_empty=false \
+        skia_use_libpng_encode=true \
+        skia_use_libpng_decode=true \
+        skia_enable_skgpu_v1=true \
+        skia_use_dng_sdk=false \
+        skia_use_egl=false \
+        skia_use_expat=false \
+        skia_use_fontconfig=false \
+        skia_use_freetype=false \
+        skia_use_icu=false \
+        skia_use_libheif=false \
+        skia_use_system_libpng=false \
+        skia_use_libjpeg_turbo_encode=false \
+        skia_use_libjpeg_turbo_decode=false \
+        skia_use_libwebp_encode=false \
+        skia_use_libwebp_decode=false \
+        skia_use_lua=false \
+        skia_use_piex=false \
+        skia_use_vulkan=false \
+        skia_use_metal=true \
+        skia_use_angle=false \
+        skia_use_system_zlib=false \
+        skia_enable_spirv_validation=false \
+        skia_enable_pdf=false \
+        skia_enable_skottie=false \
+        skia_enable_tools=false \
+    "
+
+    case $1 in 
+        arm64) 
+            ARCH=arm64
+            FOLDER=arm64
+
+            # use Rive optimized/stripped Skia for macOS static libs.
+            bin/gn gen out/$FOLDER --type=static_library --args="   \
+            target_os=\"mac\"                                       \
+            target_cpu=\"arm64\"                                    \
+            extra_cflags=[                                          \
+                ${SHARED_EXTRA_CFLAGS}
+            ]                                                       \
+            ${SHARED_ARGS}
+            "
+            ;;
+        x64) 
+            ARCH=x64
+            FOLDER=x64
+
+            bin/gn gen out/$FOLDER --type=static_library --args="   \
+            target_os=\"mac\"                                       \
+            target_cpu=\"x64\"                                      \
+            extra_cflags=[                                          \
+                \"--target=x86_64-apple-macos10.12\",               \
+                \"-fno-rtti\",                                      \
+                \"-fno-rtti\",                                      \
+                ${SHARED_EXTRA_CFLAGS}
+            ]                                                       \
+            extra_asmflags = [                                      \
+                \"--target=x86_64-apple-macos10.12\"                \
+            ]                                                       \
+            extra_cflags_c = [                                      \
+                \"--target=x86_64-apple-macos10.12\",               \
+                \"-Wno-error\"                                      \
+            ]                                                       \
+            extra_ldflags=[                                         \
+                \"--target=x86_64-apple-macos10.12\"                \
+            ]                                                       \
+            cc = \"clang\"                                          \
+            cxx = \"clang++\"                                       \
+            ${SHARED_ARGS}
+            "
+            ;;
+        *) 
+            echo "Do not know build configuration for $1"
+            exit 1
+    esac
+    
+    ninja -C out/$FOLDER
+    cd ..
+}
+
+if is_build_cached_locally; then 
+    echo "Build is cached, nothing to do."
+else
+    if is_build_cached_remotely; then 
+        pull_cache
+    else 
+        getSkia
+        build_skia_macos $1
+        # hmm not the appiest with this guy
+        OUTPUT_CACHE=out/$FOLDER upload_cache
+    fi 
+fi
+
+cd ..