Bump io.opentelemetry.proto:opentelemetry-proto (#442)

Bumps [io.opentelemetry.proto:opentelemetry-proto](https://github.com/open-telemetry/opentelemetry-proto-java) from 0.19.0-alpha to 0.20.0-alpha.
- [Release notes](https://github.com/open-telemetry/opentelemetry-proto-java/releases)
- [Commits](https://github.com/open-telemetry/opentelemetry-proto-java/commits)

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

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

Author: dependabot[bot]

dependencyManagement/build.gradle.kts

@@ -74,7 +74,7 @@ val DEPENDENCIES = listOf(
   "com.squareup.okhttp3:okhttp:4.11.0",
   "io.opentelemetry.contrib:opentelemetry-aws-xray:1.27.0",
   "io.opentelemetry.contrib:opentelemetry-aws-resources:1.26.0-alpha",
-  "io.opentelemetry.proto:opentelemetry-proto:0.19.0-alpha",
+  "io.opentelemetry.proto:opentelemetry-proto:0.20.0-alpha",
   "io.opentelemetry.javaagent:opentelemetry-javaagent:${if (!TEST_SNAPSHOTS) otelVersion else "$otelSnapshotVersion-SNAPSHOT"}",
   "net.bytebuddy:byte-buddy:1.14.4"
 )