fix(deps): update postcard to get rid of yanked critical-section (#2810)

## Description

Update postcard to get rid of yanked critical-section dep

## Breaking Changes

None

## Notes & open questions

None

## Change checklist

- [x] Self-review.
- [x] ~~Documentation updates following the [style
guide](https://rust-lang.github.io/rfcs/1574-more-api-documentation-conventions.html#appendix-a-full-conventions-text),
if relevant.~~
- [x] ~~Tests if relevant.~~
- [x] ~~All breaking changes documented.~~

Author: rklaehn