return transport errors that support errors.Is

[dprotaso]

Previously timed out requests could be checked using errors.Is(err, context. DeadlineExceeded)

That changed when multiple errors were returned in an earlier PR. This change introduces Uber's multi-err library that coalesces errors and supports error.Is

[codecov-commenter]

Codecov Report

Merging #1244 (9b514d6) into main (a2e5b9e) will decrease coverage by 0.02%.
The diff coverage is 100.00%.

❗ Current head 9b514d6 differs from pull request most recent head 05d164f. Consider uploading reports for the commit 05d164f to get more accurate results

@@            Coverage Diff             @@
##             main    #1244      +/-   ##
==========================================
- Coverage   73.87%   73.84%   -0.03%     
==========================================
  Files         111      111              
  Lines        8263     8263              
==========================================
- Hits         6104     6102       -2     
- Misses       1557     1559       +2     
  Partials      602      602              

Impacted Files	Coverage Δ
pkg/v1/remote/transport/ping.go	91.46% <100.00%> (ø)
pkg/v1/remote/multi_write.go	62.92% <0.00%> (-0.98%)	⬇️

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[imjasonh]

Nice.