用 grep -E 代替 egrep

[ReeseWang]

egrep 已经被弃用了，我的 certbot 执行的时候会报错：

Hook '--manual-auth-hook' for [redacted] ran with error output:                                                                                                                     
 egrep: warning: egrep is obsolescent; using grep -E 

[justjavac]

thx