Bioschema type linked to Learning Resource doesn't not exist

[dpshelio]

Maybe related with #481 but opening as a separate issue as this is using something that it doesn't exist now.

https://github.com/carpentries/sandpaper/blob/d03c89cd0fa3931a82df26aa15388efab7cf4e9b/inst/templates/metadata-template.txt#L7C1-L7C84

I don't yet have a suggestion to use something else (like TrainingMaterial from Bioschema or LearningResource from Schema).

[froggleston]

Can I confirm that the fix is to:

• keep the "@type": "LearningResource",
• change the "dct:conformsTo": "https://bioschemas.org/profiles/LearningResource/1.0-RELEASE", back to "dct:conformsTo": "https://bioschemas.org/profiles/TrainingMaterial/1.0-RELEASE",