Update okhttpclient dependency to allow 5.x.x

[Reweuser17]

We want to update okhttpclient in our project to 5.3.0. Okhttpclient 5.x.x has been out since July. The last stable version before that (4.12.0) hasn't received an update since 2023 and has a boatload of open bugs, some of which cause real problems in our application.

But the commercetools sdk sadly enforces okhttpclient [4.12.0,4.99999] strictly, so this is blocking us from updating okhttpclient.

https://github.com/commercetools/commercetools-sdk-java-v2/blob/main/commercetools/commercetools-okhttp-client4/build.gradle

There's not a lot of big changes in okhttpclient 5.x.x compared to 4.12.0, but a large number of bugfixes, so it shouldn't be too difficult to update that.