"Port is not an integer" when init connection

Describe the bug
When init a connection , throws tortoise.exceptions.ConfigurationError: Port is not an integer exception.
I guess maybe it caused by the password charaters.

To Reproduce
Steps to reproduce the behavior, preferaby a small code snippet.

from tortoise import Tortoise, run_async


async def init():
    # Here we create a SQLite DB using file "db.sqlite3"
    #  also specify the app name of "models"
    #  which contain models from "app.models"
    await Tortoise.init(
        db_url='mysql://root:1233onDB57#2020@myhost.com:33060/cs_app',
        modules={'models': ['common.models']}
    )
    # Generate the schema
    await Tortoise.generate_schemas()


# run_async is a helper function to run simple async Tortoise scripts.
run_async(init())

The error message:

Traceback (most recent call last):
  File "/Users/maxwen/.conda/envs/csvw-spider/lib/python3.8/site-packages/tortoise/backends/base/config_generator.py", line 98, in expand_db_url
    if vmap.get("port") and url.port:
  File "/Users/maxwen/.conda/envs/csvw-spider/lib/python3.8/urllib/parse.py", line 177, in port
    raise ValueError(message) from None
ValueError: Port could not be cast to integer value as '1233onDB57'

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/Users/xxx/Projects/python/csvw-spider/webapi/test.py", line 19, in <module>
    run_async(init())
  File "/Users/xxx/.conda/envs/csvw-spider/lib/python3.8/site-packages/tortoise/__init__.py", line 707, in run_async
    loop.run_until_complete(coro)
  File "/Users/xxx/.conda/envs/csvw-spider/lib/python3.8/asyncio/base_events.py", line 616, in run_until_complete
    return future.result()
  File "/Users/xxx/Projects/python/csvw-spider/webapi/test.py", line 10, in init
    await Tortoise.init(
  File "/Users/xxx/.conda/envs/csvw-spider/lib/python3.8/site-packages/tortoise/__init__.py", line 558, in init
    config = generate_config(db_url, modules)
  File "/Users/xxx/.conda/envs/csvw-spider/lib/python3.8/site-packages/tortoise/backends/base/config_generator.py", line 125, in generate_config
    "connections": {_connection_label: expand_db_url(db_url, testing)},
  File "/Users/xxx/.conda/envs/csvw-spider/lib/python3.8/site-packages/tortoise/backends/base/config_generator.py", line 101, in expand_db_url
    raise ConfigurationError("Port is not an integer")
tortoise.exceptions.ConfigurationError: Port is not an integer

Expected behavior
A clear and concise description of what you expected to happen.

Additional context
Add any other context about the problem here.

Start with tortoise/backends/base/config_generator.py, especially expand_db_url(), and reproduce the shown MySQL connection URL. Trace how urllib.parse handles the URL and verify the resulting configuration does not raise the reported ConfigurationError; add or update a focused regression test if the repository contains relevant configuration tests.