Allow warnings when validating podspec

Ideally, this should be removed once the warnings have been addressed

.buildkite/pipeline.yml

@@ -25,7 +25,7 @@ steps:
   - label: "🔬 Validate Podspecs"
     key: "validate"
     command: |
-      validate_podspec
+      validate_podspec --allow-warnings
     plugins: *common_plugins
 
   #################