ios build: Run "Update to recommended settings" for ZulipMobile project.

Done on Xcode "Version 12.5 (12E262)" in the GUI; screenshot at
  #4887 (comment).

Done to follow some of the template-app changes in
facebook/react-native@6685aba46, on the path to the RN v0.64
upgrade. In particular, this bullet point:

> - Update to recommended settings for Xcode 12

I didn't use a similar option that presented itself for the Pods
project.

(We don't make any changes corresponding to the "Add -e to the
bundle images script" bullet point; see
  https://chat.zulip.org/#narrow/stream/243-mobile-team/topic/RN.20v0.2E64.20upgrade.3A.20Xcode.20config.20changes.3F/near/1209893.)

ios/ZulipMobile.xcodeproj/project.pbxproj

@@ -79,7 +79,6 @@
 			isa = PBXGroup;
 			children = (
 				ED297162215061F000B7C4FE /* JavaScriptCore.framework */,
-				ED2971642150620600B7C4FE /* JavaScriptCore.framework */,
 				74F3CD22CB932FA7EEE0BB66 /* libPods-ZulipMobile.a */,
 			);
 			name = Frameworks;
@@ -173,7 +172,7 @@
 		83CBB9F71A601CBA00E9B192 /* Project object */ = {
 			isa = PBXProject;
 			attributes = {
-				LastUpgradeCheck = 1160;
+				LastUpgradeCheck = 1250;
 				TargetAttributes = {
 					13B07F861A680F5B00A75B9A = {
 						DevelopmentTeam = 66KHCWMEYB;
@@ -413,7 +412,7 @@
 				FRAMEWORK_SEARCH_PATHS = "$(inherited)";
 				HEADER_SEARCH_PATHS = "$(inherited)";
 				INFOPLIST_FILE = ZulipMobile/Info.plist;
-				IPHONEOS_DEPLOYMENT_TARGET = 11.0;
+				IPHONEOS_DEPLOYMENT_TARGET = 12.0;
 				LD_RUNPATH_SEARCH_PATHS = "$(inherited) @executable_path/Frameworks";
 				OTHER_LDFLAGS = (
 					"$(inherited)",
@@ -443,7 +442,7 @@
 				FRAMEWORK_SEARCH_PATHS = "$(inherited)";
 				HEADER_SEARCH_PATHS = "$(inherited)";
 				INFOPLIST_FILE = ZulipMobile/Info.plist;
-				IPHONEOS_DEPLOYMENT_TARGET = 11.0;
+				IPHONEOS_DEPLOYMENT_TARGET = 12.0;
 				LD_RUNPATH_SEARCH_PATHS = "$(inherited) @executable_path/Frameworks";
 				OTHER_LDFLAGS = (
 					"$(inherited)",
@@ -483,6 +482,7 @@
 				CLANG_WARN_OBJC_IMPLICIT_RETAIN_SELF = YES;
 				CLANG_WARN_OBJC_LITERAL_CONVERSION = YES;
 				CLANG_WARN_OBJC_ROOT_CLASS = YES_ERROR;
+				CLANG_WARN_QUOTED_INCLUDE_IN_FRAMEWORK_HEADER = YES;
 				CLANG_WARN_RANGE_LOOP_ANALYSIS = YES;
 				CLANG_WARN_STRICT_PROTOTYPES = YES;
 				CLANG_WARN_SUSPICIOUS_MOVE = YES;
@@ -545,6 +545,7 @@
 				CLANG_WARN_OBJC_IMPLICIT_RETAIN_SELF = YES;
 				CLANG_WARN_OBJC_LITERAL_CONVERSION = YES;
 				CLANG_WARN_OBJC_ROOT_CLASS = YES_ERROR;
+				CLANG_WARN_QUOTED_INCLUDE_IN_FRAMEWORK_HEADER = YES;
 				CLANG_WARN_RANGE_LOOP_ANALYSIS = YES;
 				CLANG_WARN_STRICT_PROTOTYPES = YES;
 				CLANG_WARN_SUSPICIOUS_MOVE = YES;

ios/ZulipMobile.xcodeproj/xcshareddata/xcschemes/ZulipMobile release-mode.xcscheme

@@ -1,6 +1,6 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <Scheme
-   LastUpgradeVersion = "1160"
+   LastUpgradeVersion = "1250"
    version = "1.3">
    <BuildAction
       parallelizeBuildables = "YES"

ios/ZulipMobile.xcodeproj/xcshareddata/xcschemes/ZulipMobile.xcscheme

@@ -1,6 +1,6 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <Scheme
-   LastUpgradeVersion = "1160"
+   LastUpgradeVersion = "1250"
    version = "1.3">
    <BuildAction
       parallelizeBuildables = "YES"