Bump google-http-client from 1.21.0 to 1.39.0

Bumps [google-http-client](https://github.com/googleapis/google-http-java-client) from 1.21.0 to 1.39.0.
- [Release notes](https://github.com/googleapis/google-http-java-client/releases)
- [Changelog](https://github.com/googleapis/google-http-java-client/blob/master/CHANGELOG.md)
- [Commits](googleapis/google-http-java-client@1.21.0...v1.39.0)

Signed-off-by: dependabot[bot] <support@github.com>

pom.xml

@@ -69,7 +69,7 @@
     <java.level.test>8</java.level.test>
     <google.guava.version>30.1-jre</google.guava.version>
     <google.api.version>1.25.0</google.api.version>
-    <google.http.version>1.21.0</google.http.version>
+    <google.http.version>1.39.0</google.http.version>
     <cloudresourcemanager.revision>547</cloudresourcemanager.revision>
     <container.revision>74</container.revision>
     <gcp-plugin-core.version>0.3.0</gcp-plugin-core.version>