Refactored GPIO to be testable and gradle upgrade

[ecsedigergo]

[zsoltmazlo]

If I may interrupt, I think version upgrades are not that big a deal

[benedekh]

A general question in the end: did you test the changes together with the modules (components) which use the GpioManager? Do these components work correctly after introducing the separate classes for CommandWriter and CommandReader in GpioManager?

[ecsedigergo]

General answer: First of all I did not have yet opportunity and the knowledge to test it, but its true, its necessary before the merge.

[benedekh]

If I may interrupt, I think version upgrades are not that big a deal

@zsoltmazlo There are two issues which might arise:

1. some internal code might broke within the modules if they heavily rely on some specific features of the dependencies.
2. every gradle project ought to use the same version of the dependency to avoid incompatibility / inconsistency issues. ('Everyone should be on the same page.' as the saying goes.)

[ecsedigergo]

I wanted to use JUnit 5 and for that I had to upgrade the versions.

[benedekh]

@ecsedigergo Argument is accepted. If it does not cause any compilation (/ runtime) problems, then the version upgrade is good to go.