Add vcpkg.json for the QtGRPC chat example

Use the vcpkg manifest to configure and build QtGRPC chat example.
This allows automating the dependency installation using vcpkg.

Pick-to: 6.9
Task-number: QTBUG-132738
Change-Id: Iafcb8e144d51f1af0d775869550f003c997d106a
Reviewed-by: Alexandru Croitor <alexandru.croitor@qt.io>

examples/grpc/chat/vcpkg.json

@@ -0,0 +1,23 @@
+{
+    "$schema": "https://raw.githubusercontent.com/microsoft/vcpkg-tool/main/docs/vcpkg.schema.json",
+    "description": "Simple chat based on the Qt GRPC client API.",
+    "dependencies": [
+        "protobuf",
+        "grpc"
+    ],
+    "features": {
+        "vcpkg-qt": {
+            "description": "Use Qt libraries from vcpkg",
+            "dependencies": [
+                {
+                    "name": "qtgrpc",
+                    "version>=": "6.9"
+                },
+                {
+                    "name": "qtdeclarative",
+                    "version>=": "6.9"
+                }
+            ]
+        }
+    }
+}