style: Consistently use single quotes for string literals in code

git_time_tracker/__main__.py

@@ -20,7 +20,7 @@ def filter_samples(
     sample_filter: set[str],
 ) -> list[ActivitySample]:
     if not sample_filter:
-        raise ValueError("sample_filter must not be empty")
+        raise ValueError('sample_filter must not be empty')
     return [s for s in samples if set(s.labels).intersection(sample_filter)]
 
 

tests/test_myanimelist.py

@@ -4,7 +4,7 @@ from personal_data.fetchers.myanimelist import parse_name
 
 
 @pytest.mark.parametrize(
-    ("input_str", "expected_group1", "expected_group2"),
+    ('input_str', 'expected_group1', 'expected_group2'),
     [
         ('"Soundscape"', 'Soundscape', None),
         ('"Soundscape (サウンドスケープ)"', 'Soundscape', 'サウンドスケープ'),