Current branch diff-target is up to date.

commit 94c825919320bf3d3e2608b823dc887ed6122413
Author: Valentin Lorentz <vlorentz@softwareheritage.org>
Date:   Mon Nov 2 13:47:51 2020 +0100

    Remove metadata deletion endpoints and algorithms
    
    This was expected to be used in these two cases:
    
    1. if we remove mappings or file detection from a metadata indexer
    2. if an origin removes all its metadata files
    
    but:
    
    1. if we do so, then we should bump the indexer version, so the
       old metadata will be preserved anyway, as different indexer
       versions get different indexer_configuration_ids
    2. this should be a rather rare even, and even if it happens, we
       might want to keep the old metadata anyway rather than
       nothing (even if it's outdated), for search purposes.
    
    Additionally, this commit is motivated by:
    
    * that's less issues to deal with when writing to Kafka (the journal
      writer currently doesn't support suppression; and we would also have
      to add support for deletion in all consumers)
    * less code (~250 lines)