CircleCI 2.0 compatibility

[heavelock]

What does this PR do?

Changes the config of CircleCI to be compatible with CircleCI 2.0. The CircleCI 1.0 was EOLed on 31st of Agust, 2018.
https://circleci.com/blog/sunsetting-1-0/

Why was it initiated? Any relevant Issues?

Nope.

PR Checklist

• Correct base branch selected? master for new features, maintenance_... for bug fixes
• This PR is not directly related to an existing issue (which has no PR yet).
• If the PR is making changes to documentation, docs pages can be built automatically.
  Just remove the space in the following string after the + sign: "+ DOCS"
• If any network modules should be tested for the PR, add them as a comma separated list
  (e.g. clients.fdsn,clients.arclink) after the colon in the following magic string: "+TESTS:"
  (you can also add "ALL" to just simply run all tests across all modules)
• All tests still pass.
• Any new features or fixed regressions are be covered via new tests.
• Any new or changed features have are fully documented.
• Significant changes have been added to CHANGELOG.txt .
• First time contributors have added your name to CONTRIBUTORS.txt .

[heavelock]

Okay, ready for review.

[megies]

Minor nitpick, but looks good to me and seems to work in CircleCI

[megies]

conda activate ... is what they propose nowadays

[heavelock]

Oh, I was not even aware that they unified linux with windows in terms of that. Thanks!

[heavelock]

Well, it seems that conda activate doesn't work on this docker image. The conda itself proposes adding lines to .bashrc but it will be easier to revert to source activate instead.

[megies]

Well, it seems that conda activate doesn't work on this docker image. The conda itself proposes adding lines to .bashrc but it will be easier to revert to source activate instead.

Ah OK, yeah, then just use the old style, I guess. Whatever works..

[krischer]

Cool! Thanks for this :-)