Add go-1.17-compatible build directives

[evantorrie]

go-1.17 adds a new go build constraint format for inclusion at the head of *.go files. This PR adds the new go-1.17 compatible build constraint format, while keeping the pre go-1.17 format for compatibility.

The reason for this PR is to avoid make precommit with a go-1.17 compiler/linting toolset from wanting to modify these files every time it's run.

[codecov]

Codecov Report

Merging #2263 (348d7b4) into main (28f335e) will increase coverage by 0.0%.
The diff coverage is n/a.

@@          Coverage Diff          @@
##            main   #2263   +/-   ##
=====================================
  Coverage   72.4%   72.5%           
=====================================
  Files        168     168           
  Lines      11872   11872           
=====================================
+ Hits        8606    8616   +10     
+ Misses      3031    3024    -7     
+ Partials     235     232    -3     

Impacted Files	Coverage Δ
sdk/resource/os_unix.go	75.0% <ø> (ø)
sdk/metric/sdk.go	81.6% <0.0%> (+1.4%)	⬆️
...s/otlp/otlptrace/internal/connection/connection.go	16.4% <0.0%> (+1.5%)	⬆️
sdk/metric/refcount_mapped.go	100.0% <0.0%> (+20.0%)	⬆️

[pellared]

You can do the same for other GOOSes 😉