Make the v4 docs active.

Also updates the migration guide with information about `IterableMiddlewarePipeInterface`

Signed-off-by: George Steel <[email protected]>

docs/book/v4/migration.md

@@ -36,6 +36,10 @@ public function __construct(ResponseFactoryInterface $responseFactory){}
 
 ## Changes in public interfaces
 
+### MiddlewarePipe is now Iterable
+
+`MiddlewarePipe` now implements a new interface `IterableMiddlewarePipeInterface`. This makes the pipeline iterable and provides a way of inspecting the composed middleware. 
+
 ### Signature changes
 
 - `Laminas\Stratigility\Handler\NotFoundHandler::__construct()`: the parameter `$responseFactory` changed from `callable` to `Psr\Http\Message\ResponseFactoryInterface`.

mkdocs.yml

@@ -2,13 +2,25 @@ docs_dir: docs/book
 site_dir: docs/html
 extra:
   project: Components
-  current_version: v3
+  current_version: v4
   versions:
+    - v4
     - v3
     - v2
     - v1
 nav:
     - Home: index.md
+    - v4:
+      - Intro: v4/intro.md
+      - Reference:
+          - "Installation and Requirements": v4/install.md
+          - Usage: v4/usage.md
+          - Middleware: v4/middleware.md
+          - "Error Handlers": v4/error-handlers.md
+          - "Creating Middleware": v4/creating-middleware.md
+          - "Composing middleware": v4/executing-middleware.md
+          - "API Reference": v4/api.md
+          - Migration: v4/migration.md
     - v3:
       - Intro: v3/intro.md
       - Reference:
@@ -44,11 +56,11 @@ plugins:
   - search
   - redirects:
       redirect_maps:
-        install.md: v3/install.md
-        usage.md: v3/usage.md
-        middleware.md: v3/middleware.md
-        error-handlers.md: v3/error-handlers.md
-        creating-middleware.md: v3/creating-middleware.md
-        executing-middleware.md: v3/executing-middleware.md
-        api.md: v3/api.md
-        migration.md: v3/migration.md
+        install.md: v4/install.md
+        usage.md: v4/usage.md
+        middleware.md: v4/middleware.md
+        error-handlers.md: v4/error-handlers.md
+        creating-middleware.md: v4/creating-middleware.md
+        executing-middleware.md: v4/executing-middleware.md
+        api.md: v4/api.md
+        migration.md: v4/migration.md