Fix Firestore internal test deployment target

Author: a-maurice

firestore/integration_test_internal/Podfile

@@ -9,7 +9,7 @@ target 'integration_test' do
 end
 
 target 'integration_test_tvos' do
-  platform :tvos, '12.0'
+  platform :tvos, '13.0'
   pod 'Firebase/Firestore', '11.0.0'
   pod 'Firebase/Auth', '11.0.0'
 end

firestore/integration_test_internal/integration_test.xcodeproj/project.pbxproj

@@ -948,7 +948,7 @@
 				SWIFT_OPTIMIZATION_LEVEL = "-Onone";
 				SWIFT_VERSION = 5.3;
 				TARGETED_DEVICE_FAMILY = 3;
-				TVOS_DEPLOYMENT_TARGET = 12.0;
+				TVOS_DEPLOYMENT_TARGET = 13.0;
 			};
 			name = Debug;
 		};
@@ -1018,7 +1018,7 @@
 				SDKROOT = appletvos;
 				SWIFT_VERSION = 5.3;
 				TARGETED_DEVICE_FAMILY = 3;
-				TVOS_DEPLOYMENT_TARGET = 12.0;
+				TVOS_DEPLOYMENT_TARGET = 13.0;
 			};
 			name = Release;
 		};