Bump SQLAlchemy to 2.0 (#626)

* `SQLALCHEMY_WARN_20=1` fixed all removed warnings.

* fix some mypy errors

* fix fetchone

* make format

* ignore annotations

* let's try like this?

* remove

* make format

* Update pyproject.toml

Co-authored-by: Pavol Rusnak <pavol@rusnak.io>

* extract _mapping in fetchone() and fetchall() + fix poetry lock

* fix

* make format

* fix integer indexing of row fields

* Update cashu/mint/crud.py

---------

Co-authored-by: Pavol Rusnak <pavol@rusnak.io>
Co-authored-by: callebtc <93376500+callebtc@users.noreply.github.com>

cashu/wallet/crud.py

@@ -377,7 +377,7 @@ async def bump_secret_derivation(
         )
         counter = 0
     else:
-        counter = int(rows[0])
+        counter = int(rows["counter"])
 
     if not skip:
         await (conn or db).execute(
@@ -437,8 +437,8 @@ async def get_seed_and_mnemonic(
     )
     return (
         (
-            row[0],
-            row[1],
+            row["seed"],
+            row["mnemonic"],
         )
         if row
         else None