Add gradle task rule for marking the next version

[solonovamax]

Adds a gradle task rule for incrementing the next version, using the format markNextVersion[Patch/Minor/Major/MinorIfNotRelease/Prerelease/Branch]

Fixes #602

Downsides of this approach:

• Tasks are not present in the ide, so it's hard for users to know about them

Upsides of this approach:

• Does not pollute the task list with a bunch of tasks
• Tasks for incrementing the version are only created immediately before the task is executed
• No need to add new tasks if any new version incrementers are added

[solonovamax]

Marked as a draft, as I'm unsure if this is the best approach, instead of just creating several tasks.

in #602, I said:

Hi, I've implemented this using task rules, however there is currently somewhat of a drawback:

it will not show the task in the ide.

with task rules, it allows you to specify the next marked version by doing

gradle run markNextVersion[Patch/Minor/Major/MinorIfNotRelease/Prerelease/Branch]

and then it will use the appropriate version incrementer. however, since these tasks technically don't actually exist until right before they're invoked, the ide has absolutely no knowledge of them. (basically you can tell gradle "if a task matches this pattern, then run this code right before attempting to execute the task", and the code that it runs creates the task with name of the task its about to run)

I'm debating whether or not I might just want to create a couple of dedicated tasks called

• markNextVersionPatch
• markNextVersionMinor
• markNextVersionMajor
• etc.

that way, they'd actually show up inside of the gradle sidebar in intellij, for greater discoverability.

Opinions?