If you don't need a parameter, don't include it. You could for example create a metadata file that only contained an author parameter, or a metadata file that included every parameter except a version number.
(Note: parameter order doesn't matter, and that each parameter is optional Starbound will load just fine without it.
The metadata file contains general information about the mod, much of which will be displayed in mod's information section via the mod list on the Starbound title screen. Should these parameters be needed in a Steam upload, they will need to be manually added prior to uploading. Rather than install a mod by overwriting assets you can take advantage of an incredibly simple mod loader that is already built into the game. It should be noted, however, that the uploader does not have fields for "requires", "includes", "priority" or "link", but will not harm any already contained in the file. Simply click the normal play from Steam, and select the "Launch Mod Uploader Tool" and follow along with the instructions. This will automatically generate a metadata file for you. If you are using Steam for windows, you can upload a mod using the Mod Uploader Tool. It's been suggested to either use _metadata for the filename, or name it.
(Note: Windows generally takes issue with any file that starts with a period. metadata and is placed at the root of a mod's folder. The metadata file can be named either _metadata or. It's an entirely optional JSON file that contains a set of entirely optional parameters. modinfo file as of version 1.0 (Cheerful Giraffe, released July 22nd, 2016).