build: treat warnings as errors (#235)

* build: treat warnings as errors

* filter protobuf warning

Author: parthea

packages/google-cloud-runtimeconfig/pytest.ini

@@ -0,0 +1,9 @@
+[pytest]
+filterwarnings =
+    # treat all warnings as errors
+    error
+    # Remove once release PR https://github.com/googleapis/python-api-common-protos/pull/191 is merged
+    ignore:.*pkg_resources.declare_namespace:DeprecationWarning
+    ignore:.*pkg_resources is deprecated as an API:DeprecationWarning
+    # Remove once https://github.com/protocolbuffers/protobuf/issues/12186 is fixed
+    ignore:.*custom tp_new.*in Python 3.14:DeprecationWarning