build(deps): bump certifi from 2021.5.30 to 2021.10.8

Bumps [certifi](https://github.com/certifi/python-certifi) from 2021.5.30 to 2021.10.8.
- [Release notes](https://github.com/certifi/python-certifi/releases)
- [Commits](certifi/python-certifi@2021.05.30...2021.10.08)

---
updated-dependencies:
- dependency-name: certifi
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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

requirements-pinned.txt

@@ -1,4 +1,4 @@
-certifi==2021.5.30        # via requests
+certifi==2021.10.8        # via requests
 cffi==1.14.6              # via cryptography, pynacl
 charset-normalizer==2.0.6 # via requests
 cryptography==3.4.8       # via securesystemslib