az devops login fails to add PAT to Mac OS keychain

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

## Describe the bug

**Command Name**
`az devops login
Extension Name: azure-devops. Version: 0.13.0.`

**Errors:**
```
Can't store password on keychain
Traceback (most recent call last):
azure-devops/keyring/backends/OS_X.py, ln 36, in set_password
self.keychain, service, username, password)
azure-devops/keyring/backends/_OS_X_API.py, ln 247, in set_generic_password
NotFound.raise_for_status(status, "Unable to set password")
azure-devops/keyring/backends/_OS_X_API.py, ln 50, in raise_for_status
Error.raise_for_status(status, msg)
azure-devops/keyring/backends/_OS_X_API.py, ln 42, in raise_for_status
raise cls(status, msg)
keyring.backends._OS_X_API.Error: (-25308, 'Unable to set password')

...

azure-devops/keyring/backends/OS_X.py, ln 38, in set_password
raise PasswordSetError("Can't store password on keychain")
keyring.errors.PasswordSetError: Can't store password on keychain
```

## 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 devops login`

## Expected Behavior

## Environment Summary
```
Darwin-19.2.0-x86_64-i386-64bit
Python 3.7.4
Shell: bash

azure-cli 2.0.74 *

Extensions:
azure-devops 0.13.0

```
## Additional Context