Change CTRL_C_EVENT to the SIGINT signal, as PyCharm does not handle CTRL_C_EVENT signals.

[liuyiyangwang]

Summary

Unfortunately, starting from uvicorn 0.21.1, when developing with PyCharm, reload cannot terminate the process properly. Change CTRL_C_EVENT to the SIGINT signal, as PyCharm does not handle CTRL_C_EVENT signals.

os.kill(self.process.pid, signal.CTRL_C_EVENT) -- >> os.kill(self.process.pid, signal.SIGINT)

I am certain that this is an issue with PyCharm. Unfortunately, they haven't responded to my feedback. I hope the author can make a compromise and merge this pull request, as it addresses a significant usability issue.