update docs

receiver/statsdreceiver/README.md

@@ -33,6 +33,8 @@ The Following settings are optional:
 
 - `enable_metric_type: true`(default value is false): Enable the statsd receiver to be able to emit the metric type(gauge, counter, timer(in the future), histogram(in the future)) as a label.
 
+- `enable_simple_tags: true`(default value is false): Enable parsing tags that do not have a value, e.g. `#mykey` instead of `#mykey:myvalue`. DogStatsD supports such tagging.
+
 - `is_monotonic_counter` (default value is false): Set all counter-type metrics the statsd receiver received as monotonic.
 
 - `timer_histogram_mapping:`(default value is below): Specify what OTLP type to convert received timing/histogram data to.