[Maven Extension] Add Tracer instrumentationVersion (ie otel.library.version) (#191)

* Add Trace instrumentationVersion

* Simplify code

Author: cyrille-leclerc

maven-extension/build.gradle.kts

@@ -49,6 +49,9 @@ configure<PublishingExtension> {
 
 tasks {
   shadowJar {
+    manifest {
+      attributes["Implementation-Version"] = project.version
+    }
     archiveClassifier.set("")
   }
 

maven-extension/src/main/java/io/opentelemetry/maven/OpenTelemetrySdkService.java

@@ -25,6 +25,9 @@
 @Component(role = OpenTelemetrySdkService.class, hint = "opentelemetry-service")
 public final class OpenTelemetrySdkService implements Initializable, Disposable {
 
+  public static final String VERSION =
+      OpenTelemetrySdkService.class.getPackage().getImplementationVersion();
+
   private static final Logger logger = LoggerFactory.getLogger(OpenTelemetrySdkService.class);
 
   private OpenTelemetry openTelemetry = OpenTelemetry.noop();
@@ -76,7 +79,7 @@ public synchronized void dispose() {
 
   @Override
   public void initialize() {
-    logger.debug("OpenTelemetry: initialize OpenTelemetrySdkService...");
+    logger.debug("OpenTelemetry: Initialize OpenTelemetrySdkService v{}...", VERSION);
 
     // Change default of "otel.traces.exporter" from "otlp" to "none"
     // The impacts are
@@ -106,7 +109,7 @@ public void initialize() {
             .getBoolean("otel.instrumentation.maven.mojo.enabled");
     this.mojosInstrumentationEnabled = mojoSpansEnabled == null ? true : mojoSpansEnabled;
 
-    this.tracer = this.openTelemetry.getTracer("io.opentelemetry.contrib.maven");
+    this.tracer = openTelemetry.getTracer("io.opentelemetry.contrib.maven", VERSION);
   }
 
   public Tracer getTracer() {