deps: update core dependencies (#48)

Author: renovate-bot

pom.xml

@@ -66,9 +66,9 @@
     <google.core.version>1.91.1</google.core.version>
     <google.api-common.version>1.8.1</google.api-common.version>
     <google.common-protos.version>1.17.0</google.common-protos.version>
-    <google.auth.version>0.19.0</google.auth.version>
+    <google.auth.version>0.20.0</google.auth.version>
     <gax.version>1.53.0</gax.version>
-    <grpc.version>1.26.0</grpc.version>
+    <grpc.version>1.27.0</grpc.version>
     <protobuf.version>3.11.1</protobuf.version>
     <junit.version>4.13</junit.version>
     <guava.version>28.2-android</guava.version>