Add documentation

docs/src/main/asciidoc/deploying-to-kubernetes.adoc

@@ -467,6 +467,23 @@ This would generate the following in the `env` section of your container:
         optional: false
 ----
 
+It's also possible to add a prefix when you are generating env from Secret, the following configuration creates environment variable from Secret with key `foo` adding a prefix `BAR`:
+
+[source,properties]
+----
+quarkus.kubernetes.env.secrets=foo[BAR]
+----
+
+This would generate the following in the `env` section of your container:
+[source,yaml]
+----
+- env:
+    envFrom:
+    - secretRef:
+        name: foo
+      prefix: BAR
+----
+
 ===== Environment variables from ConfigMap
 
 To add all key/value pairs from `ConfigMap` as environment variables just apply the following configuration, separating each
@@ -512,6 +529,23 @@ This would generate the following in the `env` section of your container:
         optional: false
 ----
 
+It's also possible to add a prefix when you are generating env from ConfigMap, the following configuration creates environment variable from ConfigMap with key `foo` adding a prefix `BAR`:
+
+[source,properties]
+----
+quarkus.kubernetes.env.configmaps=foo[BAR]
+----
+
+This would generate the following in the `env` section of your container:
+[source,yaml]
+----
+- env:
+    envFrom:
+    - configMapRef:
+        name: foo
+      prefix: BAR
+----
+
 ===== Environment variables from fields
 
 It's also possible to use the value from another field to add a new environment variable by specifying the path of the field to be used as a source, as follows:

extensions/kubernetes/spi/src/main/java/io/quarkus/kubernetes/spi/KubernetesEnvBuildItem.java

@@ -77,8 +77,7 @@ public static KubernetesEnvBuildItem createSimpleVar(String name, String value,
     }
 
     public static KubernetesEnvBuildItem createFromConfigMapKey(String varName, String key, String configmap, String target,
-            String prefix,
-            boolean... oldStyle) {
+            String prefix, boolean... oldStyle) {
         return create(varName, key, null, configmap, null, target, prefix, isOldStyle(oldStyle));
     }