Update the metric Export interface to accept a *ResourceMetrics instead of ResourceMetrics

[unicod3]

Resolves #3852

Hello, I am not sure if that requires a change log, I can update it if it does.

Updated the change log

[codecov]

Codecov Report

Merging #3853 (6542d83) into main (3a40e65) will decrease coverage by 0.1%.
The diff coverage is 100.0%.

Additional details and impacted files

@@           Coverage Diff           @@
##            main   #3853     +/-   ##
=======================================
- Coverage   81.6%   81.5%   -0.1%     
=======================================
  Files        169     169             
  Lines      12723   12711     -12     
=======================================
- Hits       10383   10371     -12     
  Misses      2121    2121             
  Partials     219     219             

Impacted Files	Coverage Δ
bridge/opencensus/metric.go	92.5% <100.0%> (ø)
exporters/otlp/otlpmetric/internal/exporter.go	67.2% <100.0%> (ø)
...s/otlp/otlpmetric/internal/transform/metricdata.go	100.0% <100.0%> (ø)
exporters/stdout/stdoutmetric/exporter.go	91.8% <100.0%> (-0.9%)	⬇️
sdk/metric/periodic_reader.go	91.8% <100.0%> (ø)

... and 2 files with indirect coverage changes

[MrAlias]

Resolves #3852

Hello, I am not sure if that requires a change log, I can update it if it does.

Thanks for the contribution! Please do add a changelog entry for the exported Exporter interface change so exporter authors know to update things.