Update dependency axios

[cschwaderer]

nominatim-geocoder depends on axios, setting version ^0.16.1 in its package.json. However, axios is vulnerable to DoS attacks until version 0.18. So, you might want to update nominatim-geocoder's package.json to resolve version 0.18.1 or 0.19 of axios
See here: https://www.npmjs.com/advisories/880