Set to null by default (#15194)

Signed-off-by: Naseem <naseemkullah@gmail.com>

stable/fluent-bit/Chart.yaml

@@ -1,6 +1,6 @@
 apiVersion: v1
 name: fluent-bit
-version: 2.2.0
+version: 2.3.0
 appVersion: 1.2.1
 description: Fast and Lightweight Log/Data Forwarder for Linux, BSD and OSX
 keywords:

stable/fluent-bit/README.md

@@ -98,7 +98,7 @@ The following table lists the configurable parameters of the Fluent-Bit chart an
 | `filter.kubeTag`                   | Optional top-level tag for matching in filter         | `kube`                                 |
 | `filter.kubeTagPrefix`             | Optional tag prefix used by Tail   | `kube.var.log.containers.`                                |
 | `filter.mergeJSONLog`              | If the log field content is a JSON string map, append the map fields as part of the log structure         | `true`                                 |
-| `filter.mergeLogKey`               | If set, append the processed log keys under a new root key specified by this variable. | log_processed |
+| `filter.mergeLogKey`               | If set, append the processed log keys under a new root key specified by this variable. | `nil` |
 | `image.fluent_bit.repository`      | Image                                      | `fluent/fluent-bit`                               |
 | `image.fluent_bit.tag`             | Image tag                                  | `1.1.3`                                          |
 | `image.pullPolicy`                 | Image pull policy                          | `IfNotPresent`                                          |

stable/fluent-bit/values.yaml

@@ -237,7 +237,7 @@ filter:
 
 # If set, all unpacked keys from mergeJSONLog (Merge_Log) will be packed under
 # the key name specified on mergeLogKey (Merge_Log_Key)
-  mergeLogKey: log_processed
+  mergeLogKey: ""
 
 # If true, enable the use of monitoring for a pod annotation of
 # fluentbit.io/parser: parser_name. parser_name must be the name