remove method from pyi that no longer exists (#12942)

Author: reaperhulk

src/cryptography/hazmat/bindings/_rust/x509.pyi

@@ -198,7 +198,6 @@ class CertificateSigningRequest:
     def tbs_certrequest_bytes(self) -> bytes: ...
     @property
     def is_signature_valid(self) -> bool: ...
-    def get_attribute_for_oid(self, oid: x509.ObjectIdentifier) -> bytes: ...
 
 class PolicyBuilder:
     def time(self, time: datetime.datetime) -> PolicyBuilder: ...