[7.0] Update protobuf version (#44451)

Author: wtgodbe

eng/Versions.props

@@ -247,7 +247,7 @@
     <CommandLineParserVersion>2.3.0</CommandLineParserVersion>
     <FSharpCoreVersion>6.0.0</FSharpCoreVersion>
     <GoogleApiCommonProtosVersion>2.5.0</GoogleApiCommonProtosVersion>
-    <GoogleProtobufVersion>3.21.5</GoogleProtobufVersion>
+    <GoogleProtobufVersion>3.21.6</GoogleProtobufVersion>
     <GrpcAspNetCoreVersion>2.49.0</GrpcAspNetCoreVersion>
     <GrpcAspNetCoreServerVersion>2.49.0</GrpcAspNetCoreServerVersion>
     <GrpcAuthVersion>2.49.0</GrpcAuthVersion>