Cannot locate jwt package in app_check.py after updating to firebase-admin-python V6.0.0

### [REQUIRED] Step 2: Describe your environment



  * Operating System version: MacOS 10.15.7 

  * Firebase SDK version: `V6.0.0`

  * Firebase Product: `app_check`

  * Python version: 3.7.9

  * Pip version: 22.1.2



### [REQUIRED] Step 3: Describe the problem

Updated to V6.0.0 and attempted to run my development server within Flask and encountered the following errors:



```

Error: While importing 'api', an ImportError was raised:



Traceback (most recent call last):

  File "/Users/kdfriedman/Desktop/curate-ai-python-api/env/lib/python3.7/site-packages/flask/cli.py", line 218, in locate_app

    __import__(module_name)

  File "/Users/kdfriedman/Desktop/curate-ai-python-api/api/api.py", line 2, in <module>

    from auth import validate_auth, validate_app

  File "/Users/kdfriedman/Desktop/curate-ai-python-api/api/auth.py", line 2, in <module>

    from service.firebase import verify_auth_token, verify_app_token

  File "/Users/kdfriedman/Desktop/curate-ai-python-api/api/service/firebase.py", line 2, in <module>

    from firebase_admin import credentials, auth, firestore, app_check

  File "/Users/kdfriedman/Desktop/curate-ai-python-api/env/lib/python3.7/site-packages/firebase_admin/app_check.py", line 18, in <module>

    import jwt

ModuleNotFoundError: No module named 'jwt'

```



After attempting to install the jwt package to fix the issue, a new error occurred:



```

Error: While importing 'api', an ImportError was raised:



Traceback (most recent call last):

  File "/Users/kdfriedman/Desktop/curate-ai-python-api/env/lib/python3.7/site-packages/flask/cli.py", line 218, in locate_app

    __import__(module_name)

  File "/Users/kdfriedman/Desktop/curate-ai-python-api/api/api.py", line 2, in <module>

    from auth import validate_auth, validate_app

  File "/Users/kdfriedman/Desktop/curate-ai-python-api/api/auth.py", line 2, in <module>

    from service.firebase import verify_auth_token, verify_app_token

  File "/Users/kdfriedman/Desktop/curate-ai-python-api/api/service/firebase.py", line 2, in <module>

    from firebase_admin import credentials, auth, firestore, app_check

  File "/Users/kdfriedman/Desktop/curate-ai-python-api/env/lib/python3.7/site-packages/firebase_admin/app_check.py", line 19, in <module>

    from jwt import PyJWKClient, ExpiredSignatureError, InvalidTokenError

ImportError: cannot import name 'PyJWKClient' from 'jwt' (/Users/kdfriedman/Desktop/curate-ai-python-api/env/lib/python3.7/site-packages/jwt/__init__.py)

```

#### Steps to reproduce:



I updated to V6 of the SDK and immediately encountered this issue. When I attempted to install the jwt package, a different error occurred.



#### Relevant Code:



```

import firebase_admin

from firebase_admin import credentials, auth, firestore, app_check

import os



# Initialize the default app

ENV_KEYS = {

    "CREDS_GO_HERE"

}



CREDENTIALS = credentials.Certificate(ENV_KEYS)

firebase_app = firebase_admin.initialize_app(CREDENTIALS)



verify_app_token = app_check.verify_token

```

[]