deps: update io.grpc:grpc-bom to v1.36.0 (#389)

Combination of #356, #377, #386

deps: update dependency com.google.api:gax-bom to v1.62.0
deps: update dependency com.google.http-client:google-http-client-bom to v1.39.0
deps: update dependency opencensus to v0.28.0

java-core/pom.xml

@@ -151,16 +151,16 @@
     <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
     <github.global.server>github</github.global.server>
     <site.installationModule>google-cloud-core-parent</site.installationModule>
-    <gax.version>1.60.1</gax.version>
+    <gax.version>1.62.0</gax.version>
     <google.api-common.version>1.10.1</google.api-common.version>
     <google.common-protos.version>2.1.0</google.common-protos.version>
     <google.iam.version>1.0.10</google.iam.version>
     <google.auth.version>0.24.0</google.auth.version>
     <google.api.version>1.31.2</google.api.version>
-    <google.http.version>1.38.1</google.http.version>
-    <grpc.version>1.34.1</grpc.version>
+    <google.http.version>1.39.0</google.http.version>
+    <grpc.version>1.36.0</grpc.version>
     <protobuf.version>3.15.3</protobuf.version>
-    <opencensus.version>0.24.0</opencensus.version>
+    <opencensus.version>0.28.0</opencensus.version>
     <annotations-api.version>1.3.2</annotations-api.version>
     <guava.version>30.1-android</guava.version><!-- We are currently using the *-android version to support JDK7. -->
     <junit.version>4.13.2</junit.version>