Stop failing on warnings (#6807)

Author: paulb777

GoogleDataTransport.podspec

@@ -42,7 +42,6 @@ Shared library for iOS SDK data transport needs.
 
   s.pod_target_xcconfig = {
     'GCC_C_LANGUAGE_STANDARD' => 'c99',
-    'GCC_TREAT_WARNINGS_AS_ERRORS' => 'YES',
     'CLANG_UNDEFINED_BEHAVIOR_SANITIZER_NULLABILITY' => 'YES',
     'GCC_PREPROCESSOR_DEFINITIONS' =>
       # The nanopb pod sets these defs, so we must too. (We *do* require 16bit

GoogleDataTransport/CHANGELOG.md

@@ -1,3 +1,6 @@
+# Unreleased
+- Remove `GCC_TREAT_WARNINGS_AS_ERRORS` from the podspec.
+
 # v8.0.0
 - Source restructuring to limit the public API surface.