Replace httpbin.org with httpcan.org

[jfsimoneau]

Because of the recent httpbin.org outages that are failing the proxy tests, I replaced the calls to a rust-based clone called httpcan.org. Another contender is the Go-based httpbingo.org service, but they do not support Brotli or SHA-512 digests. The only difference is in the auth digest, they return the algorithm as part of the response, and I couldn't make auth-int work for some reason.

[yhirose]

Could you please add more information in the description section?

[yhirose]

Great! Could you also take a look at DigestAuthTest.FromHTTPWatch_Online error? Thanks a lot!

[yhirose]

Is there any reason why this line is disabled?

[jfsimoneau]

I couldn't make auth-int work at all. Even curl fails, so I suppose this is a limitation of httpcan.org.

[jfsimoneau]

Great! Could you also take a look at DigestAuthTest.FromHTTPWatch_Online error? Thanks a lot!

Sure. It seems to be the same limitation the original httpbin.org limitation where the username is ignored in the digest comparison. httpcan.org doesn't have that limitation, but does not support auth-int. I will use httpcan.org for the bad username test but keep nghttp2.org for the rest of the tests.

[yhirose]

Thanks! I have merged it.