try to fix ci

.github/workflows/main.yml

@@ -5,7 +5,7 @@ on: [push,pull_request]
 jobs:
   build:
 
-    runs-on: macOS-11.3
+    runs-on: macos-10.15
     
     steps:
     - uses: actions/checkout@v1

ShadowsocksX-NG.xcodeproj/project.pbxproj

@@ -1146,7 +1146,7 @@
 				GCC_C_LANGUAGE_STANDARD = gnu11;
 				INFOPLIST_FILE = "ShadowsocksX-NGTests/Info.plist";
 				LD_RUNPATH_SEARCH_PATHS = "$(inherited) @executable_path/../Frameworks @loader_path/../Frameworks";
-				MACOSX_DEPLOYMENT_TARGET = 11.3;
+				MACOSX_DEPLOYMENT_TARGET = 10.12;
 				MTL_ENABLE_DEBUG_INFO = INCLUDE_SOURCE;
 				MTL_FAST_MATH = YES;
 				PRODUCT_BUNDLE_IDENTIFIER = "com.qiuyuzhou.ShadowsocksX-NGTests";
@@ -1174,7 +1174,7 @@
 				GCC_C_LANGUAGE_STANDARD = gnu11;
 				INFOPLIST_FILE = "ShadowsocksX-NGTests/Info.plist";
 				LD_RUNPATH_SEARCH_PATHS = "$(inherited) @executable_path/../Frameworks @loader_path/../Frameworks";
-				MACOSX_DEPLOYMENT_TARGET = 11.3;
+				MACOSX_DEPLOYMENT_TARGET = 10.12;
 				MTL_FAST_MATH = YES;
 				PRODUCT_BUNDLE_IDENTIFIER = "com.qiuyuzhou.ShadowsocksX-NGTests";
 				PRODUCT_NAME = "$(TARGET_NAME)";