refactor: remove github.com/pkg/errors as dependency

[sbchaos]

No description provided.

[coveralls]

Pull Request Test Coverage Report for Build 2148571478

• 0 of 0 changed or added relevant lines in 0 files are covered.
• 176 unchanged lines in 8 files lost coverage.
• Overall coverage increased (+0.2%) to 74.77%

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Files with Coverage Reduction	New Missed Lines	%
service/namespace_service.go	2	97.18%
job/dependency_resolver.go	4	95.96%
service/job_run_service.go	8	92.19%
compiler/job_run_input_compiler.go	9	81.54%
datastore/service.go	24	89.69%
models/plugin.go	31	2.22%
api/handler/v1beta1/job_run.go	38	77.09%
job/service.go	60	84.48%

Totals
Change from base Build 2148254284:	0.2%
Covered Lines:	5933
Relevant Lines:	7935

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💛 - Coveralls