Update/go1.19

[Aneurysm9]

Update the default version of Go for the CI workflow to 1.19 and add 1.19 to the test version matrix.

The default version needs to be updated to 1.19 as the latest version of golangci-lint requires 1.19. This then drives the need to eliminate the use of io/ioutil and make gofmt changes.

[codecov]

Codecov Report

Merging #2675 (6e91c80) into main (ac4bad7) will not change coverage.
The diff coverage is 50.0%.

@@          Coverage Diff          @@
##            main   #2675   +/-   ##
=====================================
  Coverage   74.4%   74.4%           
=====================================
  Files        145     145           
  Lines       6681    6681           
=====================================
  Hits        4973    4973           
  Misses      1561    1561           
  Partials     147     147           

Impacted Files	Coverage Δ
detectors/aws/ec2/ec2.go	89.0% <ø> (ø)
detectors/aws/ecs/ecs.go	54.7% <0.0%> (ø)
detectors/aws/eks/detector.go	35.6% <0.0%> (ø)
...tation/github.com/labstack/echo/otelecho/config.go	100.0% <ø> (ø)
instrumentation/net/http/otelhttp/config.go	87.8% <ø> (ø)
propagators/aws/xray/idgenerator.go	100.0% <ø> (ø)
propagators/b3/b3_config.go	100.0% <ø> (ø)
propagators/b3/b3_propagator.go	99.0% <ø> (ø)
...mplers/jaegerremote/internal/utils/rate_limiter.go	100.0% <ø> (ø)
samplers/probability/consistent/base2.go	100.0% <ø> (ø)
... and 3 more