add nullaway to spring

Author: zeitlinger

instrumentation/spring/spring-web/spring-web-3.1/javaagent/build.gradle.kts

@@ -1,5 +1,6 @@
 plugins {
   id("otel.javaagent-instrumentation")
+  id("otel.nullaway-conventions")
 }
 
 muzzle {

instrumentation/spring/spring-web/spring-web-6.0/javaagent/build.gradle.kts

@@ -1,5 +1,6 @@
 plugins {
   id("otel.javaagent-instrumentation")
+  id("otel.nullaway-conventions")
 }
 
 muzzle {

instrumentation/spring/spring-web/spring-web-6.0/javaagent/src/main/java/io/opentelemetry/javaagent/instrumentation/spring/web/v6_0/RestTemplateInstrumentation.java

@@ -37,6 +37,7 @@ public void transform(TypeTransformer transformer) {
   public static class UrlTemplateAdvice {
 
     @Advice.OnMethodEnter(suppress = Throwable.class)
+    @Nullable
     public static Scope onEnter(@Advice.Argument(1) String uriTemplate) {
       if (uriTemplate != null) {
         String path = UrlParser.getPath(uriTemplate);