Feature/substrate 0.9.42 (#262)

### Description
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### Types of Changes
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- [ ] Tech Debt (Code improvements)
- [ ] Bug fix (non-breaking change which fixes an issue)
- [ ] New feature (non-breaking change which adds functionality)
- [ ] Breaking change (fix or feature that would cause existing
functionality to change)
- [x] Dependency upgrade (A change in substrate or any 3rd party crate
version)

### Migrations and Hooks
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- [x] This change requires a runtime migration.
- [ ] Modifies `on_initialize`
- [ ] Modifies `on_finalize`

### Checklist
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requiring PR review -->
- [x] Change has been tested locally.
- [x] Change adds / updates tests.
- [ ] Changelog doc updated.

---------

Co-authored-by: rakanalh <[email protected]>

CHANGELOG.md

@@ -11,6 +11,9 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [vNext]
 
+## [4.8.9]
+
+- [C,D] Updated Substrate to polkadot-v0.9.42
 - Introduce a burn rate of 0.058% daily to bring inflation down.
 - More explicit events in `pallet-ddc-payouts` about batch index
 - ...