Update backoff requirement from ~=2.0 to ~=2.2

Updates the requirements on [backoff](https://github.com/litl/backoff) to permit the latest version.
- [Release notes](https://github.com/litl/backoff/releases)
- [Changelog](https://github.com/litl/backoff/blob/master/CHANGELOG.md)
- [Commits](litl/backoff@v2.0.0...v2.2.1)

---
updated-dependencies:
- dependency-name: backoff
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <[email protected]>

requirements_test.txt

@@ -1,5 +1,5 @@
 pytest-homeassistant-custom-component==0.12.20
 
 # Component dependencies
-backoff~=2.0
+backoff~=2.2
 aiolimiter~=1.0