build: treat warnings as errors (#803)

Author: parthea

packages/google-cloud-firestore/pytest.ini

@@ -0,0 +1,16 @@
+[pytest]
+filterwarnings =
+    # treat all warnings as errors
+    error
+    # Remove once https://github.com/protocolbuffers/protobuf/issues/12186 is fixed
+    ignore:.*custom tp_new.*in Python 3.14:DeprecationWarning
+    # Remove once https://github.com/googleapis/python-api-common-protos/pull/187/files is merged
+    ignore:.*pkg_resources.declare_namespace:DeprecationWarning
+    ignore:.*pkg_resources is deprecated as an API:DeprecationWarning
+    # Remove once https://github.com/googleapis/python-firestore/issues/804 is fixed
+    ignore:.*Detected filter using positional arguments:UserWarning
+    # Remove once https://github.com/googleapis/python-firestore/pull/716 is merged
+    ignore:datetime.datetime.utcfromtimestamp\(\) is deprecated:DeprecationWarning    
+    ignore:datetime.datetime.utcnow\(\) is deprecated:DeprecationWarning
+    # Remove once https://github.com/grpc/grpc/issues/35086 is fixed
+    ignore:There is no current event loop:DeprecationWarning:grpc.aio._channel