Skip updating Gradle when already updated

[shanman190]

What's changed?

Skip performing extra work when the current Gradle version was updated earlier in the cycle.

What's your motivation?

Overall reduce what would be considered duplicate work due to ordering within the recipe stack. For most cases, the stack will include Gradle updates that incrementally go higher. However, users may pull in recipes in varying orders, so we should ensure that we do the minimum amount of work necessary.

Anyone you would like to review specifically?

Any of: @jkschneider @sambsnyd @timtebeek

Have you considered any alternatives or workarounds?

Only one really is to try to strictly order recipes in the recipe stack as a user, so that things always go up and never down. Though this can be harder than it sounds.

Checklist

• I've added unit tests to cover both positive and negative cases
• I've read and applied the recipe conventions and best practices
• I've used the IntelliJ IDEA auto-formatter on affected files

[timtebeek]

Looks good to me; thanks for adding this logic!