docs: price-feeder v0.2.1 changelog update (#779) (#780)

## Description

Adds the 0.2.1 release to the price feeder changelog

----

### Author Checklist

*All items are required. Please add a note to the item if the item is not applicable and
please add links to any relevant follow up issues.*

I have...

- [ ] included the correct [type prefix](https://github.com/commitizen/conventional-commit-types/blob/v3.0.0/index.json) in the PR title
- [ ] added appropriate labels to the PR
- [ ] added `!` to the type prefix if API or client breaking change
- [ ] targeted the correct branch (see [PR Targeting](https://github.com/umee-network/umee/blob/main/CONTRIBUTING.md#pr-targeting))
- [ ] provided a link to the relevant issue or specification
- [ ] added a changelog entry to `CHANGELOG.md`
- [ ] included comments for [documenting Go code](https://blog.golang.org/godoc)
- [ ] updated the relevant documentation or specification
- [ ] reviewed "Files changed" and left comments if necessary
- [ ] confirmed all CI checks have passed

### Reviewers Checklist

*All items are required. Please add a note if the item is not applicable and please add
your handle next to the items reviewed if you only reviewed selected items.*

I have...

- [ ] confirmed the correct [type prefix](https://github.com/commitizen/conventional-commit-types/blob/v3.0.0/index.json) in the PR title
- [ ] confirmed `!` in the type prefix if API or client breaking change
- [ ] confirmed all author checklist items have been addressed
- [ ] reviewed state machine logic
- [ ] reviewed API design and naming
- [ ] reviewed documentation is accurate
- [ ] reviewed tests and test coverage
- [ ] manually tested (if applicable)

(cherry picked from commit 841e2f0)

Co-authored-by: Adam Wozniak <29418299+adamewozniak@users.noreply.github.com>

price-feeder/CHANGELOG.md

@@ -45,6 +45,8 @@ Ref: https://keepachangelog.com/en/1.0.0/
 
 ## [Unreleased]
 
+## [v0.2.1](https://github.com/umee-network/umee/releases/tag/price-feeder%2Fv0.2.1) - 2022-04-06
+
 ### Improvements
 
 - [#766](https://github.com/umee-network/umee/pull/766) Update deps to use umee v2.0.0.