feat: Make License mandatory for plugins submitted to meltanohub

[rawwar]

reference discussion link: https://meltano.slack.com/archives/C024T93P0AJ/p1683318763082389

Reason: This can help from using sources which have restrictive licenses. Make better informed choices when choosing a plugin

[pnadolny13]

@rawwar thanks for logging this! I also created #1307 to document these standards and what to do with existing plugins that dont meet the standard.

[edgarrmondragon]

https://spdx.org/licenses/ is a good resource to get a list of valid license IDs

[rawwar]

Also, all the ones that are currently default.. if they don't have a license.. we should probably remove them as default. And also include a note about missing license.. if anyone's trying to download them.

I'm proposing that because, licenses are probably the first thing orgs look at when using them. So, I think its important we highlight that.

[tayloramurphy]

@pnadolny13 per @rawwar's comment, do you know which plugins are default that don't have a license? I would agree that the default variant should have a license, especially if there are multiple variants available.

[pnadolny13]

@tayloramurphy it actually looks like a fair amount of them dont have a license including some on MeltanoLabs so I created MeltanoLabs/Meta#46. I also would love to see meltano/sdk#235 get implemented with a default, some users just simply forget about a license.

[edgarrmondragon]

@pnadolny13 see meltano/sdk#1709

[rawwar]

Just wondering, is it ok to update meltanohub repo's Github actions' with a task to checkout the repo and check if the license file exists? and if not.. fail it?

[pnadolny13]

@rawwar I think thats a great idea! It can be added as another CI workflow https://github.com/meltano/hub/tree/main/.github/workflows.