Update CI URLs to point to new caching infrastructure

[omus]

Hello there!
This is an automated pull request submitted by @staticfloat to help package authors transition their Julia installation CI setups to the new binary provider URL. Please take a look at this PR, and if there is a problem or it doesn't download correctly when CI runs, feel free to ping @staticfloat

[coveralls]

Coverage remained the same at 96.154% when pulling 423ff5e on updated_ci_url into 6b435a1 on master.

[codecov-io]

Codecov Report

Merging #5 into master will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master       #5   +/-   ##
=======================================
  Coverage   96.15%   96.15%           
=======================================
  Files           1        1           
  Lines         104      104           
=======================================
  Hits          100      100           
  Misses          4        4

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