chore: drop unrelated contributing doc drift

Signed-off-by: Gregor Zeitlinger <gregor.zeitlinger@grafana.com>

Author: zeitlinger

CONTRIBUTING.md

@@ -4,7 +4,7 @@ Welcome to the OpenTelemetry Semantic Convention Java repository!
 
 ## Building
 
-Java 21 or higher is required to build the projects in this repository
+Java 17 or higher is required to build the projects in this repository
 (the built artifacts can be used on Java 8 or higher).
 To check your Java version, run:
 
@@ -36,5 +36,5 @@ generate semantic conventions classes from the release contents.
 
 ## Style guide
 
-This repository follows the OpenTelemetry Java repository's
-[coding patterns](https://github.com/open-telemetry/opentelemetry-java/blob/main/docs/knowledge/README.md).
+This repository follows the OpenTelemetry Java
+repository's [style guide](https://github.com/open-telemetry/opentelemetry-java/blob/main/CONTRIBUTING.md#style-guideline).