ignore version in pg_dump and throw warning

cashu/core/migrations.py

@@ -36,7 +36,18 @@ async def backup_database(db: Database, version: int = 0) -> str:
     elif db.type in {POSTGRES, COCKROACH}:
         filepath = f"{filepath}.dump"
         logger.info(f"Creating {db.type} backup of {db.name} db to {filepath}")
-        os.system(f"pg_dump --dbname={db.db_location} --file={filepath}")
+        try:
+            os.system(f"pg_dump --dbname={db.db_location} --file={filepath}")
+        except Exception as e:
+            logger.error(
+                f"Error creating backup of {db.name} db: {e}. Run with"
+                " BACKUP_DB_MIGRATION=False to disable backups before database"
+                " migrations."
+            )
+            logger.warning("Trying pg_dump with option to ignore version mismatch")
+            os.system(
+                f"pg_dump --ignore-version --dbname={db.db_location} --file={filepath}"
+            )
 
     return filepath