fix: make manifest property "main" required, to match specification.md. resolves #2

Author: nytamin

v1-draft-0/examples/l3rd-name/manifest.json

@@ -4,6 +4,7 @@
     "description": "Name lower third",
     "id": "l3rd-name",
     "version": "0",
+    "main": "graphic.mjs",
     "author": {
         "name": "Johan Nyman, SuperFly.tv"
     },
@@ -32,6 +33,5 @@
             }
         }
     },
-    "asd": 123,
     "v_myLittleNote": "Vendor-specific properties can be added using the 'v_' prefix, like this!"
 }

v1-draft-0/examples/minimal/manifest.json

@@ -3,6 +3,7 @@
     "name": "Minimal Test Graphic",
     "description": "This Graphic includes the bare minimum required to be a valid OGraf Graphic. It displays a 'Hello World!' message.",
     "id": "minimal-example",
+    "main": "graphic.mjs",
     "supportsRealTime": true,
     "supportsNonRealTime": false
 }

v1-draft-0/examples/ograf-logo/manifest.json

@@ -3,6 +3,7 @@
     "name": "Minimal Test Graphics",
     "description": "This Graphic shows an OGraf logo",
     "id": "minimal-logo",
+    "main": "graphic.mjs",
     "supportsRealTime": true,
     "supportsNonRealTime": false,
     "author": {

v1-draft-0/specification/json-schemas/graphics/schema.json

@@ -83,6 +83,7 @@
         "$schema",
         "id",
         "name",
+        "main",
         "supportsRealTime",
         "supportsNonRealTime"
     ],