Update dependencies to allow GTMSessionFetcher 2.x (#207)

* Update podspec deps to allow GTMSessionFetcher 2.x

* Update SPM deps to allow GTMSessionFetcher 2.x

GoogleSignIn.podspec

@@ -34,7 +34,7 @@ The Google Sign-In SDK allows users to sign in with their Google account from th
   s.osx.framework = 'AppKit'
   s.dependency 'AppAuth', '~> 1.5'
   s.dependency 'GTMAppAuth', '~> 1.3'
-  s.dependency 'GTMSessionFetcher/Core', '~> 1.1'
+  s.dependency 'GTMSessionFetcher/Core', '>= 1.1', '< 3.0'
   s.resource_bundle = {
     'GoogleSignIn' => ['GoogleSignIn/Sources/{Resources,Strings}/*']
   }

Package.swift

@@ -52,7 +52,7 @@ let package = Package(
     .package(
       name: "GTMSessionFetcher",
       url: "https://github.com/google/gtm-session-fetcher.git",
-      "1.5.0" ..< "2.0.0"),
+      "1.5.0" ..< "3.0.0"),
     .package(
       name: "OCMock",
       url: "https://github.com/firebase/ocmock.git",