chore(deps): update GSON and Guava (#843)

* chore(deps): update GSON and Guava
* Update error_prone to match guava

dependencies.properties

@@ -39,10 +39,10 @@ maven.com_google_auth_google_auth_library_credentials=com.google.auth:google-aut
 maven.io_opencensus_opencensus_api=io.opencensus:opencensus-api:0.24.0
 maven.io_opencensus_opencensus_contrib_grpc_metrics=io.opencensus:opencensus-contrib-grpc-metrics:0.24.0
 maven.io_opencensus_opencensus_contrib_http_util=io.opencensus:opencensus-contrib-http-util:0.24.0
-maven.com_google_code_gson_gson=com.google.code.gson:gson:2.8.5
-maven.com_google_guava_guava=com.google.guava:guava:28.1-android
+maven.com_google_code_gson_gson=com.google.code.gson:gson:2.8.6
+maven.com_google_guava_guava=com.google.guava:guava:28.2-android
 maven.com_google_code_findbugs_jsr305=com.google.code.findbugs:jsr305:3.0.2
-maven.com_google_errorprone_error_prone_annotations=com.google.errorprone:error_prone_annotations:2.3.3
+maven.com_google_errorprone_error_prone_annotations=com.google.errorprone:error_prone_annotations:2.3.4
 maven.com_google_j2objc_j2objc_annotations=com.google.j2objc:j2objc-annotations:1.3
 maven.com_google_auto_value_auto_value=com.google.auto.value:auto-value:1.4
 maven.com_google_api_api_common=com.google.api:api-common:1.8.1