Respect minAppVersion when installing/updating plugins

[nothingislost]

It would be helpful if BRAT could respect the minAppVersion from manifest.json to avoid installing or updating any plugins that are incompatible with the user's current Obsidian version. There's a number of breaking changes in Obsidian 0.15.x and it's difficult to beta test them via BRAT since non 0.15.x users will get the updates via BRAT even though the minAppVersion is set.

One step further would be to also respect versions.json which lets you know which version of the plugin you should step down to in the case of an incompatibility.