Add lint rule duplicateRelations

[k1LoW]

No description provided.

[codecov]

Codecov Report

Merging #139 into master will decrease coverage by 1%.
The diff coverage is 85.18%.

@@            Coverage Diff             @@
##           master     #139      +/-   ##
==========================================
- Coverage   69.16%   68.15%   -1.01%     
==========================================
  Files          12       12              
  Lines        2630     2657      +27     
==========================================
- Hits         1819     1811       -8     
- Misses        622      661      +39     
+ Partials      189      185       -4

Impacted Files	Coverage Δ
config/lint.go	88.52% <85.18%> (-0.95%)	⬇️
datasource/datasource.go	20.85% <0%> (-19.02%)	⬇️

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