Refactor integration of Apache HttpClient 5.5

[gcatanese]

Feature summary

Refactor usage of deprecated method and adopt best practices

Problem statement

In #1596 the Apache HttpClient dependency has been upgraded to v5.5. The new version deprecate several methods, requiring a refactoring of the AdyenHttpClient class.

This shall be planned in major release

Proposed solution

Refactor the code that integrates Apache HttpClient 5.5 to adopt the best practices.

Alternatives considered

No response

Additional context

No response

[stijnn17]

Hi, my colleague created #1586 which was closed because of #1596 but that last one only bumped the version instead of also doing the refactoring to use the new methods. When is this refactoring planned for because we are rather anxiously waiting for this.

[gcatanese]

Hey @stijnn17, we are not planning to perform the refactoring now, but we plan the release of a new version (that works with Apache Http Client 5.5) on week 50 (from Dec 7th).

The refactoring to avoid using deprecated methods is important, but it doesn't affect the library or your integration.