fix: _pid_alive treats an out-of-C-int-range pid as not alive (no OverflowError)

os.kill(pid, 0) raises OverflowError for a pid too large for a C int, which _pid_alive did
not catch; a foreign <base>.<huge-number>.tmp file in the store dir then made every stale-tmp
sweep (so every _save) crash. an over-range pid can't name a live process, so it's treated as
not-alive like ProcessLookupError.

Signed-off-by: disqualifier <dev@disqualifier.me>

src/aiokv/aiokv.py

@@ -170,7 +170,8 @@ class AioKV:
         """check whether pid refers to a live process, without permission to signal counting as alive"""
         try:
             os.kill(pid, 0)
-        except ProcessLookupError:
+        except (ProcessLookupError, OverflowError):
+            # OverflowError: a pid too large for a C int can't name a live process
             return False
         except PermissionError:
             return True