Bump bat-native-ledger for monthly value

[jasonrsadler]

Resolves brave-intl/bat-native-ledger#32

Submitter Checklist:

• Submitted a ticket for my issue if one did not already exist.
• Used Github auto-closing keywords in the commit message.
• Added/updated tests for this change (for new code or code which already has tests).
• Ran git rebase -i to squash commits (if needed).
• Tagged reviewers and labelled the pull request as needed.
• Request a security/privacy review as needed.
• Add appropriate QA labels (QA/Needed or QA/No-QA-Needed) to include the closed issue in milestone

Test Plan:

1. Start brave clean and enable rewards
2. Refresh rewards and observe autocontribute list
3. Quit brave and open ledger_state
4. change fee_amount to a value other than a value from the default list
5. Restart brave and ensure the value is added to the list

Reviewer Checklist:

• New files have MPL-2.0 license header.
• Request a security/privacy review as needed.
• Adequate test coverage exists to prevent regressions
• Verify test plan is specified in PR before merging to source

[jasonrsadler]

master: 1725bec
0.55.x: 484b3c9