Support enabling concurrency (#438)

diff --git a/helm/openwhisk/templates/invoker-pod.yaml b/helm/openwhisk/templates/invoker-pod.yaml
index 1247ec8..e6a985a 100644
--- a/helm/openwhisk/templates/invoker-pod.yaml
+++ b/helm/openwhisk/templates/invoker-pod.yaml
@@ -116,6 +116,9 @@
           - name: "CONFIG_whisk_docker_containerFactory_containerArgs_network"
             value: {{ .Values.invoker.containerFactory.networkConfig.name | quote }}
 
+          - name: "CONFIG_whisk_containerFactory_containerArgs_extraArgs_env_0"
+            value: "__OW_ALLOW_CONCURRENT={{ .Values.invoker.containerFactory.enableConcurrency }}"
+
           # Invoker name is the name of the node (DaemonSet) or pod (StatefulSet)
           - name: "INVOKER_NAME"
             valueFrom:
diff --git a/helm/openwhisk/values-metadata.yaml b/helm/openwhisk/values-metadata.yaml
index 791e417..f2dfa44 100644
--- a/helm/openwhisk/values-metadata.yaml
+++ b/helm/openwhisk/values-metadata.yaml
@@ -1022,6 +1022,12 @@
           value: "docker"
         - label: "kubernetes"
           value: "kubernetes"
+    enableConcurrency:
+      __metadata:
+        label: "Enable concurrency"
+        description: "Should the invoker pass `__OW_ALLOW_CONCURRENT=true` to action containers, enabling concurrent execution in supporting runtimes"
+        type: "boolean"
+        required: true
     networkConfig:
       name:
         __metadata:
diff --git a/helm/openwhisk/values.yaml b/helm/openwhisk/values.yaml
index 9392747..e9bf7ef 100644
--- a/helm/openwhisk/values.yaml
+++ b/helm/openwhisk/values.yaml
@@ -245,6 +245,7 @@
     dind: false
     useRunc: false
     impl: "docker"
+    enableConcurrency: false
     networkConfig:
       name: "bridge"
       dns: