update xcode version because it is mandatory for App store (#933)

* update xcode version because it is mandatory for Aplestore
* update submodule quazip

azure-pipelines.yml

@@ -329,7 +329,7 @@ jobs:
 
 - job: BuildForIOs
   pool:
-    vmImage: 'macOS-10.14'
+    vmImage: 'macOS-10.15'
   steps:
   - task: NodeTool@0
     inputs:
@@ -370,14 +370,14 @@ jobs:
     displayName: 'Clone submodules'
 
   - script: |
-      sudo xcode-select -s /Applications/Xcode_11.3.1.app/Contents/Developer
+      sudo xcode-select -s /Applications/Xcode_12.1.1.app/Contents/Developer
       mkdir build && cd build;
       mkdir flatc && cd flatc;
-      cmake ../../third_party/flatbuffers -GXcode
+      cmake ../../third_party/flatbuffers -G Xcode -T buildsystem=1
       cmake --build . --config Release --target flatc
       export FLATC=`pwd`/Release/flatc
       cd ..
-      cmake -DIOS_ARCH="arm64" -DENABLE_BITCODE=NO -DIOS_DEPLOYMENT_TARGET=11.0 -DCMAKE_TOOLCHAIN_FILE=../ios/ios-cmake/ios.toolchain.cmake -DCMAKE_PREFIX_PATH="`pwd`/../Qt/5.15.2/ios/" -G Xcode -DIOS_ARCHIVE_BUILD=1 ..
+      cmake -DIOS_ARCH="arm64" -DENABLE_BITCODE=NO -DIOS_DEPLOYMENT_TARGET=11.0 -DCMAKE_TOOLCHAIN_FILE=../ios/ios-cmake/ios.toolchain.cmake -DCMAKE_PREFIX_PATH="`pwd`/../Qt/5.15.2/ios/" -G Xcode -T buildsystem=1 -DIOS_ARCHIVE_BUILD=1 ..
     displayName: 'CONFIGURE with cmake'
 
   - script: |