fix: Scheduler not compatible with BaseDupeFilter

[HairlessVillager]

Description

Fixes #293

API change: add dupefilter=None argument in Scheduler.__init__().

How Has This Been Tested?

Please describe the tests that you ran to verify your changes. Provide instructions so we can reproduce. Please also list any relevant details for your test configuration

• [] pytest
• [] Other test (please specify)

Test Configuration:

• OS version:
• Necessary Libraries (optional):

Checklist:

• [] My code follows the style guidelines of this project
• [] I have performed a self-review of my code
• [] I have commented my code, particularly in hard-to-understand areas
• [] I have made corresponding changes to the documentation
• [] My changes generate no new warnings
• [] I have added tests that prove my fix is effective or that my feature works
• [] New and existing unit tests pass locally with my changes
• [] Any dependent changes have been merged and published in downstream modules