compile_asn1_subdir: filter compiled files by .asn suffix
When I open the .asn file in vim, pySim should not attempt to read the vim .swp file as asn.1.
File "/home/moi/osmo-dev/src/pysim/pySim/esim/saip/__init__.py", line 45, in <module> asn1 = compile_asn1_subdir('saip') [...] File "<frozen codecs>", line 325, in decode UnicodeDecodeError: 'utf-8' codec can't decode byte 0xad in position 21: invalid start byte
