Update cachetools requirement from ~=5.2.0 to ~=5.5.0

Updates the requirements on [cachetools](https://github.com/tkem/cachetools) to permit the latest version.
- [Changelog](https://github.com/tkem/cachetools/blob/master/CHANGELOG.rst)
- [Commits](tkem/cachetools@v5.2.0...v5.5.0)

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

Signed-off-by: dependabot[bot] <support@github.com>

requirements.txt

@@ -17,7 +17,7 @@ backcall==0.2.0
 beautifulsoup4~=4.11.1
 bleach~=5.0.1
 broadbean==0.11.0
-cachetools~=5.2.0
+cachetools~=5.5.0
 certifi~=2022.12.7
 cffi~=1.15.1
 charset-normalizer~=3.0.1