ext/curl: update Caddyfile basicauth to basic_auth

In Caddy 2.8, `basicauth` was renamed to `basic_auth`.

This also applies `caddy fmt Caddyfile --overwrite` changes.

Author: Ayesh

ext/curl/tests/Caddyfile

@@ -12,7 +12,7 @@ respond /serverpush "main response"
 respond /serverpush/pushed "pushed response"
 push /serverpush /serverpush/pushed
 
-basicauth /http-basic-auth {
-    # bcrypt password hash for "password", calculated with 'caddy hash-password'
-    user $2a$14$yUKl9SGqVTAAqPTzLup.DefsbXXx3kfreNnzpJOUHcIrKnr5lgef2
+basic_auth /http-basic-auth {
+	# bcrypt password hash for "password", calculated with 'caddy hash-password'
+	user $2a$14$yUKl9SGqVTAAqPTzLup.DefsbXXx3kfreNnzpJOUHcIrKnr5lgef2
 }