The pipeline defined in the bulk update item here is ignored:

```
POST /_bulk
{"update":{"_id":"1","_index":"pipeline-test","pipeline":"lowercase-pipeline"}}
{"upsert":{"myField":"UPPER"},"script":{"source":"ctx._source.myField = 'CHANGED'","lang":"painless"}}
```

Only if the pipeline is defined as query string argument, then the pipeline is picked up and used to process the upset:

```
POST /_bulk?pipeline=lowercase-pipeline
{"update":{"_id":"1","_index":"pipeline-test"}}
{"upsert":{"myField":"UPPER"},"script":{"source":"ctx._source.myField = 'CHANGED'","lang":"painless"}}
```

The Bulk API should also use the pipeline defined in the bulk update item.
server/src/main/java/org/elasticsearch/action/bulk/BulkRequestParser.java
break;
                    }
                    line++;
                    
                    
                    if ("index".equals(action)) {
                        if (opType == null) {
                            indexRequestConsumer.accept(
                                new IndexRequest(index).id(id)
                                    .routing(routing)
                                    .version(version)
                                    .versionType(versionType)
                                    .setPipeline(pipeline)
                                    .setIfSeqNo(ifSeqNo)
                                    .setIfPrimaryTerm(ifPrimaryTerm)
                                    .source(sliceTrimmingCarriageReturn(data, from, nextMarker, xContentType), xContentType)
                                    .setDynamicTemplates(dynamicTemplates)
                                    .setRequireAlias(requireAlias),
                                type
                            );
                        } else {
                            indexRequestConsumer.accept(
                                new IndexRequest(index).id(id)
                                    .routing(routing)
                                    .version(version)
                                    .versionType(versionType)
                                    .create("create".equals(opType))
                                    .setPipeline(pipeline)
                                    .setIfSeqNo(ifSeqNo)
                                    .setIfPrimaryTerm(ifPrimaryTerm)