Remove explicit dependency of com.squareup.okhttp3

[wind57]

In root pom.xml we have this. So we have a bom project spring-cloud-kubernetes-dependencies, this all makes sense.

In that bom we track okhttp3 explicitly (and some other too, but these are not that important now).

At the same time, we track kubernetes-client version too. Now the problem is that kubernetes-client uses a different version of okhttp3. So, we basically override that all the time with a lower one. It's just how maven works

We should not be doing that. At the same time we can't rely on the fact that a transitive dependency will be provided to us (for the cases where our code really need okhttp3). In those cases we should include it explicitly, but the version should not be managed via bom.

This issue came into light while looking at this recent one.

[wind57]

I need to think about this a bit more