chore: log unsupported package qualifier as debug (#1340)

Logs unsupported package qualifiers at `debug` level rather than
`warning`.  The message is only meant to convey that there are new
qualifiers available in grype-db that the version of grype being used
cannot take advantage of to improve matching behavior; however, the
warning is confusing to users and may make it seem like grype is in a
broken state.

Signed-off-by: Weston Steimel <weston.steimel@anchore.com>

grype/db/v5/pkg/qualifier/from_json.go

@@ -43,7 +43,7 @@ func FromJSON(data []byte) ([]Qualifier, error) {
 			}
 			qualifiers = append(qualifiers, q)
 		default:
-			log.Warn("Skipping unsupported package qualifier: %s", k)
+			log.Debug("Skipping unsupported package qualifier: %s", k)
 			continue
 		}
 	}