composer.json: Adding myself as lead dev

composer.json

@@ -6,6 +6,11 @@
     "homepage": "http://picocms.org/",
     "license": "MIT",
     "authors": [
+        {
+            "name": "Daniel Rudolf",
+            "email": "picocms.org@daniel-rudolf.de",
+            "role": "Lead Developer"
+        },
         {
             "name": "The Pico Community",
             "homepage": "http://picocms.org/"