Update opentelemetry/proto spec

[trevor-dialpad]

A couple things done here:

1. Updated the proto based on the latest spec
2. Updated the metrics adapter to support the new spec

This should solve #293

[trevor-dialpad]

This is a draft because the metrics I'm posting from my client aren't being successfully picked up my the collector - I'm trying to figure out why that is so I can address it but I haven't found much to go off of so far. If anyone has any clue as to why these metrics won't be picked up by the opentelemetry-collector with OTLP/GRPC I'd appreciate any ideas.

[codecov]

Codecov Report

Merging #294 (ac8d3d9) into main (1c648c1) will decrease coverage by 0.89%.
The diff coverage is 30.56%.

❗ Current head ac8d3d9 differs from pull request most recent head 24d718d. Consider uploading reports for the commit 24d718d to get more accurate results

@@            Coverage Diff             @@
##             main     #294      +/-   ##
==========================================
- Coverage   75.35%   74.45%   -0.90%     
==========================================
  Files         361      361              
  Lines       22569    22789     +220     
==========================================
- Hits        17006    16968      -38     
- Misses       5563     5821     +258     

Impacted Files	Coverage Δ
...xporters/OpenTelemetryProtocol/proto/logs.pb.swift	0.00% <0.00%> (ø)
...rters/OpenTelemetryProtocol/proto/metrics.pb.swift	22.78% <ø> (+3.08%)	⬆️
...ters/OpenTelemetryProtocol/proto/resource.pb.swift	90.00% <ø> (ø)
.../OpenTelemetryProtocol/proto/trace_config.pb.swift	0.00% <0.00%> (ø)
.../OpenTelemetryProtocol/metric/MetricsAdapter.swift	32.17% <12.50%> (-0.82%)	⬇️
...orters/OpenTelemetryProtocol/proto/common.pb.swift	38.56% <36.36%> (-11.82%)	⬇️
...porters/OpenTelemetryProtocol/proto/trace.pb.swift	57.99% <53.80%> (-7.95%)	⬇️
...penTelemetryProtocol/OtlpMetricExporterTests.swift	86.60% <100.00%> (ø)
...ces/Exporters/Persistence/Storage/FileReader.swift	74.19% <0.00%> (-9.68%)	⬇️
... and 8 more

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[trevor-dialpad]

A bit more details I have since posting this draft:

1. This is the commit that caused metrics to stop working with the Otel collector as of v0.44.0. This removed the backwards compatibility to support metrics being sent based on the older spec (using "labels", "int_histogram", etc.)

2. This exactly what I did to generate the new spec. Then I went and manually updated some of the generated proto swift functions and variables to be public in order to compile.

protoc --swift_out=. opentelemetry/proto/*/*/v1/*.proto
protoc --grpc-swift_out=. opentelemetry/proto/*/*/v1/*.proto

[trevor-dialpad]

Fixed with: #300