Added beta feedback to Rates

Author: schnuerle

policy/README.md

@@ -342,6 +342,8 @@ An individual `Rule` object is defined by the following fields:
 ### Rates
 Rate-related properties can currently be specified on `rate` and `time` Rules. Note: A future MDS version will likely support rates for `count` and `speed` rules, but their behavior is currently undefined.
 
+**[Beta feature](/general-information.md#beta-features)**: *Yes (as of 1.0.0)*. [Leave feedback](https://github.com/openmobilityfoundation/mobility-data-specification/issues/674)  
+
 #### Rate Amounts
 The amount of a rate applied when this rule applies, if applicable (default zero). A positive integer rate amount represents a fee, while a negative integer represents a subsidy. Rate amounts are given in the `currency` defined in the [Policy](#policy).