squash! Upgrade type annotations syntax

Not all generic aliases (e.g. Dict, List) can be replaced before Python
3.9.

pgactivity/pg.py

@@ -2,7 +2,7 @@
 
 import logging
 import os
-from typing import Any, Callable, Sequence, TypeVar, overload
+from typing import Any, Callable, Dict, Sequence, TypeVar, overload
 
 Row = TypeVar("Row")
 
@@ -27,7 +27,7 @@
 
     __version__ = psycopg.__version__
 
-    Connection = psycopg.Connection[dict[str, Any]]
+    Connection = psycopg.Connection[Dict[str, Any]]
 
     class BytesLoader(Loader):
         def load(self, data: Buffer) -> bytes:

pgactivity/types.py

@@ -12,6 +12,7 @@
     Mapping,
     MutableSet,
     Sequence,
+    Tuple,
     TypeVar,
     Union,
     overload,
@@ -1133,7 +1134,7 @@ def toggle_pin_focused(self) -> None:
 ActivityStats = Union[
     Iterable[WaitingProcess],
     Iterable[RunningProcess],
-    tuple[Iterable[WaitingProcess], SystemInfo],
-    tuple[Iterable[BlockingProcess], SystemInfo],
-    tuple[Iterable[LocalRunningProcess], SystemInfo],
+    Tuple[Iterable[WaitingProcess], SystemInfo],
+    Tuple[Iterable[BlockingProcess], SystemInfo],
+    Tuple[Iterable[LocalRunningProcess], SystemInfo],
 ]

pgactivity/ui.py

@@ -3,7 +3,7 @@
 import time
 from argparse import Namespace
 from functools import partial
-from typing import cast
+from typing import List, cast
 
 import attr
 from blessed import Terminal
@@ -210,7 +210,7 @@ def main(
                         if is_local:
                             # TODO: Use this logic in waiting and blocking cases.
                             local_pg_procs, io_read, io_write = activities.ps_complete(
-                                cast(list[types.RunningProcess], pg_procs.items),
+                                cast(List[types.RunningProcess], pg_procs.items),
                                 sys_procs,
                                 fs_blocksize,
                             )