Merge branch 'mr/ferrara/prepare-bump-black-flake8-mypy' into 'master'

Fix mypy error to prepare bump to 1.13.0

See merge request it/e3-core!86

src/e3/os/process.py

@@ -759,7 +759,7 @@ def handler(signum: int, frame: Any) -> None:
 
                 # Wait for a sigchld signal. Note that select might
                 # be interrupted by signals thus the loop
-                select_args = [[fd_r], [], []]
+                select_args: list[list[int] | float] = [[fd_r], [], []]
                 if timeout != 0:
                     select_args.append(remain)