Generated Python client breaks log_commits `since` parameter

[arielshaqed]

since is a string with "date-time" format. OpenAPI requires a code forces incorrect OpenAPI date-time format for this, basically 2024-06-04T11:40:50Z.

The generated Python client code forces an incorrect format here by including microseconds, yielding 2024-06-04T11:40:50.765432Z. As a result the call fails with a message like:

lakefs.exceptions.BadRequestException: code: 400, reason: Bad Request, body: {'message': 'parameter "since" in query has an error: string doesn\'t match the format "date-time" (regular expression "^[0-9]{4}-(0[0-9]|10|11|12)-([0-2][0-9]|30|31)T[0-9]{2}:[0-9]{2}:[0-9]{2}(.[0-9]+)?(Z|(\\\\+|-)[0-9]{2}:[0-9]{2})?$")\nSchema:\n {\n "format": "date-time",\n "type": "string"\n }\n\nValue:\n "1970-01-01T00:00:00.000000+0000"\n'}

(Reported by a user.)