[chore]: Bump go.opentelemetry.io/otel from 1.20.0 to 1.21.0 (#2369)

Bumps [go.opentelemetry.io/otel](https://github.com/open-telemetry/opentelemetry-go) from 1.20.0 to 1.21.0.
- [Release notes](https://github.com/open-telemetry/opentelemetry-go/releases)
- [Changelog](https://github.com/open-telemetry/opentelemetry-go/blob/main/CHANGELOG.md)
- [Commits](https://github.com/open-telemetry/opentelemetry-go/compare/v1.20.0...v1.21.0)

---
updated-dependencies:
- dependency-name: go.opentelemetry.io/otel
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

vendor/go.opentelemetry.io/otel/.gitignore

@@ -14,13 +14,9 @@ go.work.sum
 gen/
 
 /example/dice/dice
-/example/fib/fib
-/example/fib/traces.txt
-/example/jaeger/jaeger
 /example/namedtracer/namedtracer
 /example/otel-collector/otel-collector
 /example/opencensus/opencensus
 /example/passthrough/passthrough
 /example/prometheus/prometheus
-/example/view/view
 /example/zipkin/zipkin

vendor/go.opentelemetry.io/otel/CHANGELOG.md

@@ -8,6 +8,20 @@ This project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.htm
 
 ## [Unreleased]
 
+## [1.21.0/0.44.0] 2023-11-16
+
+### Removed
+
+- Remove the deprecated `go.opentelemetry.io/otel/bridge/opencensus.NewTracer`. (#4706)
+- Remove the deprecated `go.opentelemetry.io/otel/exporters/otlp/otlpmetric` module. (#4707)
+- Remove the deprecated `go.opentelemetry.io/otel/example/view` module. (#4708)
+- Remove the deprecated `go.opentelemetry.io/otel/example/fib` module. (#4723)
+
+### Fixed
+
+- Do not parse non-protobuf responses in `go.opentelemetry.io/otel/exporters/otlp/otlpmetric/otlpmetrichttp`. (#4719)
+- Do not parse non-protobuf responses in `go.opentelemetry.io/otel/exporters/otlp/otlptrace/otlptracehttp`. (#4719)
+
 ## [1.20.0/0.43.0] 2023-11-10
 
 This release brings a breaking change for custom trace API implementations. Some interfaces (`TracerProvider`, `Tracer`, `Span`) now embed the `go.opentelemetry.io/otel/trace/embedded` types. Implementors need to update their implementations based on what they want the default behavior to be. See the "API Implementations" section of the [trace API] package documentation for more information about how to accomplish this.
@@ -2721,7 +2735,8 @@ It contains api and sdk for trace and meter.
 - CircleCI build CI manifest files.
 - CODEOWNERS file to track owners of this project.
 
-[Unreleased]: https://github.com/open-telemetry/opentelemetry-go/compare/v1.20.0...HEAD
+[Unreleased]: https://github.com/open-telemetry/opentelemetry-go/compare/v1.21.0...HEAD
+[1.21.0/0.44.0]: https://github.com/open-telemetry/opentelemetry-go/releases/tag/v1.21.0
 [1.20.0/0.43.0]: https://github.com/open-telemetry/opentelemetry-go/releases/tag/v1.20.0
 [1.19.0/0.42.0/0.0.7]: https://github.com/open-telemetry/opentelemetry-go/releases/tag/v1.19.0
 [1.19.0-rc.1/0.42.0-rc.1]: https://github.com/open-telemetry/opentelemetry-go/releases/tag/v1.19.0-rc.1

vendor/go.opentelemetry.io/otel/CONTRIBUTING.md

@@ -90,6 +90,10 @@ git push <YOUR_FORK> <YOUR_BRANCH_NAME>
 Open a pull request against the main `opentelemetry-go` repo. Be sure to add the pull
 request ID to the entry you added to `CHANGELOG.md`.
 
+Avoid rebasing and force-pushing to your branch to facilitate reviewing the pull request.
+Rewriting Git history makes it difficult to keep track of iterations during code review.
+All pull requests are squashed to a single commit upon merge to `main`.
+
 ### How to Receive Comments
 
 * If the PR is not ready for review, please put `[WIP]` in the title,

vendor/go.opentelemetry.io/otel/version.go

@@ -16,5 +16,5 @@ package otel // import "go.opentelemetry.io/otel"
 
 // Version is the current release version of OpenTelemetry in use.
 func Version() string {
-	return "1.20.0"
+	return "1.21.0"
 }

vendor/go.opentelemetry.io/otel/versions.yaml

@@ -14,13 +14,12 @@
 
 module-sets:
   stable-v1:
-    version: v1.20.0
+    version: v1.21.0
     modules:
       - go.opentelemetry.io/otel
       - go.opentelemetry.io/otel/bridge/opentracing
       - go.opentelemetry.io/otel/bridge/opentracing/test
       - go.opentelemetry.io/otel/example/dice
-      - go.opentelemetry.io/otel/example/fib
       - go.opentelemetry.io/otel/example/namedtracer
       - go.opentelemetry.io/otel/example/otel-collector
       - go.opentelemetry.io/otel/example/passthrough
@@ -35,14 +34,12 @@ module-sets:
       - go.opentelemetry.io/otel/sdk/metric
       - go.opentelemetry.io/otel/trace
   experimental-metrics:
-    version: v0.43.0
+    version: v0.44.0
     modules:
       - go.opentelemetry.io/otel/bridge/opencensus
       - go.opentelemetry.io/otel/bridge/opencensus/test
       - go.opentelemetry.io/otel/example/opencensus
       - go.opentelemetry.io/otel/example/prometheus
-      - go.opentelemetry.io/otel/example/view
-      - go.opentelemetry.io/otel/exporters/otlp/otlpmetric
       - go.opentelemetry.io/otel/exporters/otlp/otlpmetric/otlpmetricgrpc
       - go.opentelemetry.io/otel/exporters/otlp/otlpmetric/otlpmetrichttp
       - go.opentelemetry.io/otel/exporters/prometheus