port code to psycopg3

src/nominatim_db/version.py

@@ -31,7 +31,7 @@ class NominatimVersion(NamedTuple):
     major: int
     minor: int
     patch_level: int
-    db_patch_level: Optional[int]
+    db_patch_level: int
 
     def __str__(self) -> str:
         if self.db_patch_level is None:
@@ -47,6 +47,7 @@ class NominatimVersion(NamedTuple):
         return f"{self.major}.{self.minor}.{self.patch_level}"
 
 
+
 def parse_version(version: str) -> NominatimVersion:
     """ Parse a version string into a version consisting of a tuple of
         four ints: major, minor, patch level, database patch level