Update to Google’s latest version of GTMAppAuth

GTMAppAuth.podspec

@@ -1,7 +1,7 @@
 Pod::Spec.new do |s|
 
   s.name         = "GTMAppAuth"
-  s.version      = "0.5.1"
+  s.version      = "0.6.0"
   s.summary      = "Authorize GTM Session Fetcher requests with AppAuth via GTMAppAuth"
 
   s.description  = <<-DESC
@@ -22,6 +22,7 @@ requests with AppAuth.
   s.homepage     = "https://github.com/google/GTMAppAuth"
   s.license      = "Apache License, Version 2.0"
   s.authors      = { "William Denniss" => "wdenniss@google.com",
+                     "Zsika Phillip" => "zsika@google.com",
                    }
 
   s.source       = { :git => "https://github.com/google/GTMAppAuth.git", :tag => s.version }
@@ -43,5 +44,5 @@ requests with AppAuth.
 
   s.frameworks = 'Security', 'SystemConfiguration'
   s.dependency 'GTMSessionFetcher', '~> 1.1'
-  s.dependency 'AppAuth', '~> 0.7.0'
+  s.dependency 'AppAuth', '~> 0.9.0'
 end

Source/GTMTVAuthorizationResponse.h

@@ -69,7 +69,7 @@ extern NSString *const GTMTVDeviceTokenGrantType;
         properties are populated. Non-normative parameters are placed in the
         @c #additionalParameters dictionary.
  */
-- (nullable instancetype)initWithRequest:(GTMTVAuthorizationRequest *)request
+- (instancetype)initWithRequest:(GTMTVAuthorizationRequest *)request
     parameters:(NSDictionary<NSString *, NSObject<NSCopying> *> *)parameters
     NS_DESIGNATED_INITIALIZER;
 

Source/GTMTVAuthorizationResponse.m

@@ -99,10 +99,10 @@ @implementation GTMTVAuthorizationResponse
 
 #pragma mark - Initializers
 
-- (nullable instancetype)init
+- (instancetype)init
     OID_UNAVAILABLE_USE_INITIALIZER(@selector(initWithRequest:parameters:));
 
-- (nullable instancetype)initWithRequest:(GTMTVAuthorizationRequest *)request
+- (instancetype)initWithRequest:(GTMTVAuthorizationRequest *)request
     parameters:(NSDictionary<NSString *, NSObject<NSCopying> *> *)parameters {
   self = [super initWithRequest:request parameters:parameters];
   return self;