Update stubs

Author: dralley

pysequoia.pyi

@@ -76,12 +76,20 @@ class Sig:
     def __str__(self, /) -> str: ...
     @property
     def created(self, /) -> datetime |None: ...
+    @property
+    def expiration(self, /) -> datetime |None: ...
     @staticmethod
     def from_bytes(bytes: bytes) -> Sig: ...
     @staticmethod
     def from_file(path: str) -> Sig: ...
     @property
+    def issuer_fingerprint(self, /) -> str |None: ...
+    @property
     def issuer_fpr(self, /) -> str |None: ...
+    @property
+    def issuer_key_id(self, /) -> str |None: ...
+    @property
+    def signers_user_id(self, /) -> str |None: ...
 
 @final
 class SignatureMode: