Examples: Update the Vapor example (#8)

### Motivation

async-http-client 1.23.0 compiles with the Swift Static Linux SDK again, so it is no longer necessary to pin to 1.22.1

### Modifications

Updated `Package.resolved` in the Vapor example directory.
Add the example to the NOTICE.txt file.

### Result

The Vapor example builds with the latest versions of its dependencies.

### Test Plan

Built and ran the test example locally.

Author: euanh

Examples/HelloWorldVapor/Package.resolved

@@ -61,3 +61,14 @@ function from SwiftNIO Extras.
     * https://www.apache.org/licenses/LICENSE-2.0
   * HOMEPAGE:
     * https://github.com/swift-server/swift-nio-extras
+
+-------------------------------------------------------------------------------
+
+This product contains samples of how to use Swift Container Plugin with the
+following other projects:
+
+  * Vapor
+    * LICENSE (MIT License):
+      * https://mit-license.org
+    * HOMEPAGE:
+      * https://github.com/vapor/vapor