tdb/crick_upload: updates for python3
tdb/crick_upload: updates for python3

1. Python 3 csv takes the input in text mode instead of binary mode
2. Remove import of `string` functions which has been deprecated
3. Update `iteritems()` to `items()`

nextstrain/fauna,nextstrain/fauna,blab/nextstrain-db,blab/nextstrain-db