Switch build to epel release

[alexeykazakov]

See openshiftio/openshift.io#4618

[codecov]

Codecov Report

Merging #703 into master will increase coverage by 0.44%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           master     #703      +/-   ##
==========================================
+ Coverage   59.18%   59.63%   +0.44%     
==========================================
  Files          32       32              
  Lines        2357     2413      +56     
==========================================
+ Hits         1395     1439      +44     
- Misses        809      820      +11     
- Partials      153      154       +1

Impacted Files	Coverage Δ
controller/status.go	0% <0%> (ø)	⬆️
update/versions.go	100% <0%> (ø)	⬆️
controller/tenant.go	18.95% <0%> (+0.14%)	⬆️
environment/service.go	93.45% <0%> (+1.15%)	⬆️
tenant/tenant.go	82% <0%> (+10.12%)	⬆️

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