diff --git a/platformio/package/manifest/schema.py b/platformio/package/manifest/schema.py
index d17e6a20..416dccfd 100644
--- a/platformio/package/manifest/schema.py
+++ b/platformio/package/manifest/schema.py
@@ -89,7 +89,7 @@ class StrictListField(fields.List):
 class AuthorSchema(StrictSchema):
     name = fields.Str(required=True, validate=validate.Length(min=1, max=100))
     email = fields.Email(validate=validate.Length(min=1, max=50))
-    maintainer = fields.Bool(default=False)
+    maintainer = fields.Bool(dump_default=False)
     url = fields.Url(validate=validate.Length(min=1, max=255))
 
 
diff --git a/pytest.ini b/pytest.ini
new file mode 100644
index 00000000..03c86580
--- /dev/null
+++ b/pytest.ini
@@ -0,0 +1,5 @@
+[pytest]
+filterwarnings =
+    error
+    # Marshmallow
+    ignore:The distutils package is deprecated and slated for removal in Python 3.12. Use setuptools or check PEP 632 for potential alternatives:DeprecationWarning
\ No newline at end of file