proxy: update tokio-postgres to allow arbitrary config params (#8076)

## Problem

Fixes https://github.com/neondatabase/neon/issues/1287

## Summary of changes

tokio-postgres now supports arbitrary server params through the
`param(key, value)` method. Some keys are special so we explicitly
filter them out.

proxy/src/serverless/sql_over_http.rs

@@ -202,6 +202,7 @@ fn get_conn_info(
             options = Some(NeonOptions::parse_options_raw(&value));
         }
     }
+    ctx.set_db_options(params.freeze());
 
     let user_info = ComputeUserInfo {
         endpoint,