Switch to OAuth 2

[danieldegroot2]

Switch to OAuth 2 from HTTP Basic Auth and OAuth 1.0a. They are being deprecated.
See openstreetmap/operations#867

Or, if using osm-auth or other authentication library, make sure library is using OAuth 2 and library version is updated.

Also, it is likely OAuth 1 text in README.md is redundant and can be removed, or replaced with OAuth 2 text.

[ttomasz]

Thanks for creating the issue. This site will be replaced completely by openaedmap. As long as that happens before Oauth1.0 is completely disabled then we'll be fine. I'll leave this open to keep that in mind.