chore(deps): bump otel-instr-alpha from 2.20.1-alpha to 2.21.0-alpha

Bumps `otel-instr-alpha` from 2.20.1-alpha to 2.21.0-alpha.

Updates `io.opentelemetry.javaagent:opentelemetry-javaagent-extension-api` from 2.20.1-alpha to 2.21.0-alpha
- [Release notes](https://github.com/open-telemetry/opentelemetry-java-instrumentation/releases)
- [Changelog](https://github.com/open-telemetry/opentelemetry-java-instrumentation/blob/main/CHANGELOG.md)
- [Commits](https://github.com/open-telemetry/opentelemetry-java-instrumentation/commits)

Updates `io.opentelemetry.instrumentation:opentelemetry-ktor-3.0` from 2.20.1-alpha to 2.21.0-alpha
- [Release notes](https://github.com/open-telemetry/opentelemetry-java-instrumentation/releases)
- [Changelog](https://github.com/open-telemetry/opentelemetry-java-instrumentation/blob/main/CHANGELOG.md)
- [Commits](https://github.com/open-telemetry/opentelemetry-java-instrumentation/commits)

Updates `io.opentelemetry.instrumentation:opentelemetry-logback-appender-1.0` from 2.20.1-alpha to 2.21.0-alpha
- [Release notes](https://github.com/open-telemetry/opentelemetry-java-instrumentation/releases)
- [Changelog](https://github.com/open-telemetry/opentelemetry-java-instrumentation/blob/main/CHANGELOG.md)
- [Commits](https://github.com/open-telemetry/opentelemetry-java-instrumentation/commits)

Updates `io.opentelemetry.instrumentation:opentelemetry-logback-mdc-1.0` from 2.20.1-alpha to 2.21.0-alpha
- [Release notes](https://github.com/open-telemetry/opentelemetry-java-instrumentation/releases)
- [Changelog](https://github.com/open-telemetry/opentelemetry-java-instrumentation/blob/main/CHANGELOG.md)
- [Commits](https://github.com/open-telemetry/opentelemetry-java-instrumentation/commits)

---
updated-dependencies:
- dependency-name: io.opentelemetry.javaagent:opentelemetry-javaagent-extension-api
  dependency-version: 2.21.0-alpha
  dependency-type: direct:production
  update-type: version-update:semver-minor
- dependency-name: io.opentelemetry.instrumentation:opentelemetry-ktor-3.0
  dependency-version: 2.21.0-alpha
  dependency-type: direct:production
  update-type: version-update:semver-minor
- dependency-name: io.opentelemetry.instrumentation:opentelemetry-logback-appender-1.0
  dependency-version: 2.21.0-alpha
  dependency-type: direct:production
  update-type: version-update:semver-minor
- dependency-name: io.opentelemetry.instrumentation:opentelemetry-logback-mdc-1.0
  dependency-version: 2.21.0-alpha
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <[email protected]>

Author: dependabot[bot]

gradle/libs.versions.toml

@@ -71,7 +71,7 @@ fusionauth-jwt                 = "5.3.3"
 otel                           = "1.55.0"
 otel-alpha                     = "1.55.0-alpha"
 otel-instr                     = "2.20.1"
-otel-instr-alpha               = "2.20.1-alpha"
+otel-instr-alpha               = "2.21.0-alpha"
 otel-semconv                   = "1.37.0"
 otel-contrib                   = "1.50.0-alpha"
 otel-kotlin                    = "0.7.0"