update http gem to 3.0+

[pravi]

Only breaking change is drop of support for ruby 2.0 and 2.1 which we don't care. Fixes #320
twitter gem already moved to http 3.0 and this will help in debian packaging. We prefer to maintain only a single version of http.

[pravi]

Tests for ruby 2.2 passed, but failed for 2.3, 24 and 2.5 :(

[cben]

possibly related: vcr/vcr#695 (similar error, with http gem).

[cben]

also sounds like this was supposed to be fixed in http 3.2.1 by httprb/http#468?
however Travis failed here despite "Installing http 3.3.0".

[cben]

Close-cycling to rerun Travis in vague hope failures would go away (?) 😉
It does pass locally on 2.4.1.

UPDATE: no, fails all rubies ☹️

[cben]

Whoah, this is sporadic, depends on test order!
env TESTOPTS='--seed=10834' bundle exec rake fails.
env TESTOPTS='--seed=56466' bundle exec rake passes.
(at your commit 33fcfef. travis runs would-be-merge-to-master, which has new test cases so seeds may differ)

[cben]

Can you also relax webmock to '~> 3.0'? With latest Webmock 3.4.2 seems to fix sporadic errors (though it'd be great to debug why exactly those were happening)

[pravi]

@cben relaxed webmock as well and now tests are passing.

[cben]

Thanks! Have you by chance done any real-life testing of watching with http 3?

[P.S. My response speed is not good lately. And Mooli switched to a new job and likely won't have time for kubeclient. I'd be happy if anyone wants to join as maintainer.]

[cben]

👍 Tested watching manually, seems fine (with http 3.3.0 which is current version this PR gets). Merging.

(Should we also allow http 2.y? 3.y exists for over a year, so I feel OK dropping 2.y — if someone needs it let us know, it's not impossible)