plugin XEP-0277: better resilience to broken items: - if `author` element can't be found, `publisher` attribute, then `IQ`'s `from` attributes are used as fallback to find author jid - fix categories (tags) parsing if `author` element is not found - remove items which have failed parsing from `mbGet` results (instead of using `None`).

version: "3.6"
services:

  sat:
    image: salutatoi/sat
    build: backend

  libervia:
    image: salutatoi/libervia
    build: libervia
    depends_on:
      - sat