extension hack not working

### **This is autogenerated. Please review and update as needed.**

## Describe the bug

**Command Name**
`az hack`

**Errors:**
```
libffi.so.6: cannot open shared object file: No such file or directory
Traceback (most recent call last):
python3.8/site-packages/knack/cli.py, ln 206, in invoke
cmd_result = self.invocation.execute(args)
cli/core/commands/__init__.py, ln 554, in execute
parsed_args = self.parser.parse_args(args)
python3.8/site-packages/knack/parser.py, ln 259, in parse_args
return super(CLICommandParser, self).parse_args(args)
...
site-packages/cryptography/x509/extensions.py, ln 20, in
from cryptography.hazmat.primitives import constant_time, serialization
cryptography/hazmat/primitives/constant_time.py, ln 11, in
from cryptography.hazmat.bindings._constant_time import lib
ImportError: libffi.so.6: cannot open shared object file: No such file or directory
```

## To Reproduce:
Steps to reproduce the behavior. Note that argument values have been redacted, as they may contain sensitive information.

- _Put any pre-requisite steps here..._
- `az hack -h`

## Expected Behavior

## Environment Summary
```
Linux-5.4.0-47-generic-x86_64-with-glibc2.2.5
Python 3.8.1

azure-cli 2.1.0 *

Extensions:
hack 0.4.2
interactive 0.4.4
subscription 0.1.4
aks-preview 0.4.62
k8sconfiguration 0.1.7
azure-devops 0.17.0

```
## Additional Context