Fix the README.rst

[majidabdulred]

The line

async def main():
    coc_client = coc.EVentsClient()
    try:
        await coc.login("email", "password")
    except coc.InvalidCredentials as error:
        exit(error)

should be

async def main():
    coc_client = coc.EventsClient()
    try:
        await coc_client.login("email", "password")
    except coc.InvalidCredentials as error:
        exit(error)

in the README.rst