in marshmallow-4+ @validates accepts multiple field names, and
 decorated@validates methods receive data_key as a keyword argument.

--- a/platformio/package/manifest/schema.py
+++ b/platformio/package/manifest/schema.py
@@ -232,7 +232,7 @@ class ManifestSchema(BaseSchema):
     )
 
     @validates("version")
-    def validate_version(self, value):
+    def validate_version(self, value, **kwargs):
         try:
             value = str(value)
             assert "." in value
@@ -249,7 +249,7 @@ class ManifestSchema(BaseSchema):
             ) from exc
 
     @validates("license")
-    def validate_license(self, value):
+    def validate_license(self, value, **kwargs):
         try:
             spdx = self.load_spdx_licenses()
         except requests.exceptions.RequestException as exc: