Update README.md: support nginx-1.25.4 and openresty-1.25.3

Merge pull request #270 from chobits/for_pull_request

updated readme: new nginx version supported and example for websocket

Merge pull request #249 from chobits/for_pull_request

refactor logic of handling proxy timer

Merge pull request #228 from chobits/for_pull_request

Feature: get the time to receive the first byte of data from proxy server

Merge pull request #174 from chobits/for_pull_request

Feature: modify CONNECT response via proxy_connect_response directive

Merge pull request #115 from chobits/for_pull_request

updated README.md: updated openresty support to 1.15.8.1