* Resolve deprecations in the `RetryContextSerializationTests`

GH-470: Add `RetryTemplate.setLogger()` to avoid reflection in other places

Fixes: #470
Issue link: #470

Spring Cloud Config does mutation in the `RetryTemplate` for its system loading logger via `RetryTemplateFactory`.

* Expose setter for `logger` property to avoid reflection.
* Add `RetryTemplateBuilder.withLogger()` for convenience

Due to the absence of a `hashCode()` implementation, proxies for the `AnnotationClassOrMethodPointcut` class are regenerated each time, 
which causes them to be stored in the `org.springframework.cglib.core.internal.LoadingCache` (with `RetryConfiguration.AnnotationClassOrMethodPointcut` being part of the composite key for this object).
This results in an excessive accumulation of generated proxies in memory, ultimately leading to metaspace overflow.

…ven-extension:0.0.22