deps: update dependency com.google.api.grpc:proto-google-iam-v1 to v1…

….6.16 (#1036)

pom.xml

@@ -154,7 +154,7 @@
     <gax.version>2.19.5</gax.version>
     <google.api-common.version>2.2.2</google.api-common.version>
     <google.common-protos.version>2.10.0</google.common-protos.version>
-    <google.iam.version>1.6.15</google.iam.version>
+    <google.iam.version>1.6.16</google.iam.version>
     <google.auth.version>1.13.0</google.auth.version>
     <google.api.version>2.0.1</google.api.version>
     <google.http.version>1.42.3</google.http.version>