Update sequence encodings in SBOL3 files

[tcmitchell]

The sequence encoding URIs are changing in SBOL3 3.0.1. Update the following examples to use the new encodings:

• https://github.com/SynBioDex/SBOLTestSuite/tree/master/SBOL3/BBa_F2620_PoPSReceiver
• https://github.com/SynBioDex/SBOLTestSuite/tree/master/SBOL3/multicellular
• https://github.com/SynBioDex/SBOLTestSuite/tree/master/SBOL3/toggle_switch

Here are the Python definitions of the new encodings:

IUPAC_DNA_ENCODING = 'https://identifiers.org/edam:format_1207'
IUPAC_RNA_ENCODING = 'https://identifiers.org/edam:format_1207'
IUPAC_PROTEIN_ENCODING = 'https://identifiers.org/edam:format_1208'
INCHI_ENCODING = 'https://identifiers.org/edam:format_1197'
SMILES_ENCODING = 'https://identifiers.org/edam:format_1196'

[goksel]

Updated the examples with the new encodings.