build(deps): bump cryptography from 3.4.7 to 3.4.8

Bumps [cryptography](https://github.com/pyca/cryptography) from 3.4.7 to 3.4.8.
- [Release notes](https://github.com/pyca/cryptography/releases)
- [Changelog](https://github.com/pyca/cryptography/blob/main/CHANGELOG.rst)
- [Commits](pyca/cryptography@3.4.7...3.4.8)

---
updated-dependencies:
- dependency-name: cryptography
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

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

Author: dependabot[bot]

requirements-pinned.txt

@@ -1,7 +1,7 @@
 certifi==2021.5.30        # via requests
 cffi==1.14.6              # via cryptography, pynacl
 charset-normalizer==2.0.4 # via requests
-cryptography==3.4.7       # via securesystemslib
+cryptography==3.4.8       # via securesystemslib
 idna==3.2                 # via requests
 pycparser==2.20           # via cffi
 pynacl==1.4.0             # via securesystemslib