no problematic api changes

Author: zeitlinger

docs/apidiffs/current_vs_latest/opentelemetry-sdk.txt

@@ -1,7 +1,4 @@
 Comparing source compatibility of opentelemetry-sdk-1.53.0-SNAPSHOT.jar against opentelemetry-sdk-1.52.0.jar
-***! MODIFIED CLASS: PUBLIC FINAL io.opentelemetry.sdk.OpenTelemetrySdk  (not serializable)
-	===  CLASS FILE FORMAT VERSION: 52.0 <- 52.0
-	---! REMOVED METHOD: PUBLIC(-) void close()
 +++  NEW INTERFACE: PUBLIC(+) ABSTRACT(+) io.opentelemetry.sdk.WithShutdown  (not serializable)
 	+++  CLASS FILE FORMAT VERSION: 52.0 <- n.a.
 	+++  NEW INTERFACE: java.io.Closeable

sdk/all/src/main/java/io/opentelemetry/sdk/OpenTelemetrySdk.java

@@ -21,6 +21,7 @@
 import java.io.Closeable;
 import java.util.ArrayList;
 import java.util.List;
+import java.util.concurrent.TimeUnit;
 import java.util.concurrent.atomic.AtomicBoolean;
 import java.util.logging.Logger;
 import javax.annotation.Nullable;
@@ -117,6 +118,11 @@ public CompletableResultCode shutdown() {
     return CompletableResultCode.ofAll(results);
   }
 
+  @Override
+  public void close() {
+    shutdown().join(10, TimeUnit.SECONDS);
+  }
+
   @Override
   public String toString() {
     return "OpenTelemetrySdk{"