ci: set macOS deployment target to macOS 11.0

ffmpeg.patch

@@ -1,5 +1,5 @@
 diff --git a/ports/ffmpeg/portfile.cmake b/ports/ffmpeg/portfile.cmake
-index 35bac875b..5137c69be 100644
+index 35bac875b..b16d9cb64 100644
 --- a/ports/ffmpeg/portfile.cmake
 +++ b/ports/ffmpeg/portfile.cmake
 @@ -42,7 +42,20 @@ else()
@@ -24,7 +24,7 @@ index 35bac875b..5137c69be 100644
 
  if(VCPKG_TARGET_IS_WINDOWS)
      vcpkg_acquire_msys(MSYS_ROOT PACKAGES automake1.16)
-@@ -80,7 +92,7 @@ endif()
+@@ -80,7 +93,7 @@ endif()
  vcpkg_cmake_get_vars(cmake_vars_file)
  include("${cmake_vars_file}")
  if(VCPKG_DETECTED_MSVC)
@@ -33,3 +33,15 @@ index 35bac875b..5137c69be 100644
      set(OPTIONS "--toolchain=msvc ${OPTIONS}")
      # This is required because ffmpeg depends upon optimizations to link correctly
      string(APPEND VCPKG_COMBINED_C_FLAGS_DEBUG " -O2")
+@@ -574,6 +587,11 @@ if (NOT VCPKG_BUILD_TYPE OR VCPKG_BUILD_TYPE STREQUAL "release")
+     # We use response files here as the only known way to handle spaces in paths
+     set(crsp "${CURRENT_BUILDTREES_DIR}/${TARGET_TRIPLET}-rel/cflags.rsp")
+     string(REGEX REPLACE "-arch [A-Za-z0-9_]+" "" VCPKG_COMBINED_C_FLAGS_RELEASE_SANITIZED "${VCPKG_COMBINED_C_FLAGS_RELEASE}")
++    if(VCPKG_TARGET_IS_OSX)
++        # macosx-version-min version is set with current macOS version. So replace them to 11.0
++        string(REGEX REPLACE "-mmacosx-version-min=[0-9]+.[0-9]+" "" VCPKG_COMBINED_C_FLAGS_RELEASE_SANITIZED "${VCPKG_COMBINED_C_FLAGS_RELEASE_SANITIZED}")
++        string(APPEND VCPKG_COMBINED_C_FLAGS_RELEASE_SANITIZED " -mmacosx-version-min=11.0")
++    endif()
+     file(WRITE "${crsp}" "${VCPKG_COMBINED_C_FLAGS_RELEASE_SANITIZED}")
+     set(ldrsp "${CURRENT_BUILDTREES_DIR}/${TARGET_TRIPLET}-rel/ldflags.rsp")
+     string(REGEX REPLACE "-arch [A-Za-z0-9_]+" "" VCPKG_COMBINED_SHARED_LINKER_FLAGS_RELEASE_SANITIZED "${VCPKG_COMBINED_SHARED_LINKER_FLAGS_RELEASE}")