Added missing PDB source

misc-scripts/xref_mapping/xref_config.ini

@@ -1227,6 +1227,16 @@ prio_descr      =
 parser          = UniProtParser
 release_uri     = 
 
+[source UniProt::PDB]
+# Special source used in UniProtParser.  No species uses this source.
+name            = PDB
+download        = N
+order           = 20
+priority        = 1
+prio_descr      = 
+parser          = UniProtParser
+release_uri     = 
+
 [source Uniprot/SPTREMBL::MULTI]
 # Used by aedes_aegypti, anopheles_gambiae, apis_mellifera, bos_taurus, caenorhabditis_elegans, canis_familiaris, ciona_intestinalis, ciona_savignyi, danio_rerio, dasypus_novemcinctus, drosophila_melanogaster, echinops_telfairi, erinaceus_europaeus, felis_catus, gallus_gallus, gasterosteus_aculeatus, homo_sapiens, loxodonta_africana, macaca_mulatta, monodelphis_domestica, mus_musculus, myotis_lucifugus, ornithorhynchus_anatinus, oryctolagus_cuniculus, oryzias_latipes, pan_troglodytes, rattus_norvegicus, saccharomyces_cerevisiae, spermophilus_tridecemlineatus, takifugu_rubripes, tupaia_belangeri, xenopus_tropicalis
 name            = Uniprot/SPTREMBL