Bump cryptography from 3.4.5 to 3.4.6

Bumps [cryptography](https://github.com/pyca/cryptography) from 3.4.5 to 3.4.6.
- [Release notes](https://github.com/pyca/cryptography/releases)
- [Changelog](https://github.com/pyca/cryptography/blob/main/CHANGELOG.rst)
- [Commits](pyca/cryptography@3.4.5...3.4.6)

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

Author: dependabot[bot]

requirements-pinned.txt

@@ -1,7 +1,7 @@
 certifi==2020.12.5        # via requests
 cffi==1.14.5              # via cryptography, pynacl
 chardet==4.0.0            # via requests
-cryptography==3.4.5       ; python_version >= '3' # via securesystemslib
+cryptography==3.4.6       ; python_version >= '3' # via securesystemslib
 cryptography==3.3.2       ; python_version < '3' # via securesystemslib
 enum34==1.1.10            ; python_version < '3' # via cryptography
 idna==2.10                # via requests