Added max_open_conn in README

Signed-off-by: Alok Kumar Singh <[email protected]>

Author: akstron

receiver/sqlqueryreceiver/README.md

@@ -36,6 +36,7 @@ The configuration supports the following top-level fields:
 - `telemetry` (optional) Defines settings for the component's own telemetry - logs, metrics or traces.
   - `telemetry.logs` (optional) Defines settings for the component's own logs.
     - `telemetry.logs.query` (optional, default `false`) If set to `true`, every time a SQL query is run, the text of the query and the values of its parameters will be logged together with the debug log `"Running query"`.
+- `max_open_conn` (optional, default `0`): The maximumn number of open connections to the sql server. <= 0 means unlimited
 
 [storage_extension]: https://github.com/open-telemetry/opentelemetry-collector-contrib/tree/main/extension/storage/filestorage