Verify Credencial of config.json

[viniciussousazup]

- What I did
if user add a input of type credencial on config.json that not exist on providers return err

- How to verify it

- Description for the changelog

[codecov-commenter]

Codecov Report

Merging #322 into ritchie-2.0.0 will decrease coverage by 0.07%.
The diff coverage is n/a.

@@                Coverage Diff                @@
##           ritchie-2.0.0     #322      +/-   ##
=================================================
- Coverage          65.29%   65.21%   -0.08%     
=================================================
  Files                 78       78              
  Lines               2550     2550              
=================================================
- Hits                1665     1663       -2     
- Misses               723      725       +2     
  Partials             162      162              

Impacted Files	Coverage Δ
pkg/credential/finder.go	68.42% <ø> (ø)
pkg/formula/watcher/watcher.go	70.58% <0.00%> (-5.89%)	⬇️

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