chore: stricter mypy (#2053)

* chore: improve mypy

Signed-off-by: Henry Schreiner <henryschreineriii@gmail.com>

* chore(types): type functions in tests

Signed-off-by: Henry Schreiner <henryschreineriii@gmail.com>

* chore(types): No partial types in tests

Signed-off-by: Henry Schreiner <henryschreineriii@gmail.com>

---------

Signed-off-by: Henry Schreiner <henryschreineriii@gmail.com>

bin/make_dependency_update_pr.py

@@ -3,27 +3,29 @@
 from __future__ import annotations
 
 import os
+import subprocess
 import sys
 import textwrap
 import time
 from pathlib import Path
-from subprocess import run
 
 import click
 
 
-def shell(cmd, *, check: bool, **kwargs):
-    return run([cmd], shell=True, check=check, **kwargs)
+def shell(cmd: str, *, check: bool, **kwargs: object) -> subprocess.CompletedProcess[str]:
+    return subprocess.run([cmd], shell=True, check=check, **kwargs)  # type: ignore[call-overload, no-any-return]
 
 
-def git_repo_has_changes():
-    unstaged_changes = shell("git diff-index --quiet HEAD --", check=False).returncode != 0
-    staged_changes = shell("git diff-index --quiet --cached HEAD --", check=False).returncode != 0
+def git_repo_has_changes() -> bool:
+    unstaged_changes: bool = shell("git diff-index --quiet HEAD --", check=False).returncode != 0
+    staged_changes: bool = (
+        shell("git diff-index --quiet --cached HEAD --", check=False).returncode != 0
+    )
     return unstaged_changes or staged_changes
 
 
 @click.command()
-def main():
+def main() -> None:
     project_root = Path(__file__).parent / ".."
     os.chdir(project_root)
 
@@ -57,7 +59,7 @@ def main():
             PR generated by `{os.path.basename(__file__)}`.
             """
         )
-        run(
+        subprocess.run(
             [
                 "gh",
                 "pr",