Make --result-log compatible with Windows and turn it off by default

Author: elprans

src/geltest/_internal/cli.py

@@ -166,7 +166,6 @@ def _parse_key_value(
         "%TIMESTAMP%, it will be replaced by ISO8601 date and time. "
         "Empty string means not to write the log at all."
     ),
-    default="build/test-results/%TIMESTAMP%.json",
 )
 @click.option(
     "--include-unsuccessful",

src/geltest/_internal/results.py

@@ -299,7 +299,8 @@ def render_result(file: TextIO, result: TestResult) -> None:
 
 
 def _result_log_path(path_template: str) -> pathlib.Path | None:
-    now = str(datetime.datetime.now(datetime.timezone.utc)).replace(" ", "_")
+    ts = datetime.datetime.now(datetime.timezone.utc)
+    now = ts.isoformat(sep="T", timespec="seconds").replace(":", "-")
     path = pathlib.Path(path_template.replace("%TIMESTAMP%", now))
 
     parent_dir = path.parent