Fix the description of HTTP_READ_TIMEOUT and HTTP_WRITE_TIMEOUT in README is reversed.

[atolix]

Fix README.
If I'm wrong, please close PR.

[hachi8833]

I also guess that the lines specified is something incorrect, and the following might be better:

HTTP_WRITE_TIMEOUT: The maximum time in seconds that the server can take to write the response to the client.

[tamaloa]

I was also confused by the wording and my usual expectations configuring timeouts for client libraries (and also by the presence of this PR).

But the current documentation correctly describes timeouts from the perspective of this library.

For Thruster a write timeout determines how long it may write to a given client (which would be a read timeout from the clients perspective).