Add no-longer-optional fields to system metadata

systems/egg-discrimination/metadata.yml

@@ -1,6 +1,8 @@
 origin:
   name: egg-discrimination
   source: https://github.com/facebookresearch/EGG
+  upstream_source: https://github.com/facebookresearch/EGG
+  paper: null
 system:
   game_type: signalling
   game_subtype: discrimination

systems/egg-discrimination/system.json

@@ -1,7 +1,9 @@
 {
   "origin": {
     "name": "egg-discrimination",
-    "source": "https://github.com/facebookresearch/EGG"
+    "source": "https://github.com/facebookresearch/EGG",
+    "upstream_source": "https://github.com/facebookresearch/EGG",
+    "paper": null
   },
   "system": {
     "game_type": "signalling",

systems/egg-reconstruction/metadata.yml

@@ -1,6 +1,8 @@
 origin:
   name: egg-reconstruction
   source: https://github.com/facebookresearch/EGG
+  upstream_source: https://github.com/facebookresearch/EGG
+  paper: null
 system:
   game_type: signalling
   game_subtype: reconstruction

systems/egg-reconstruction/system.json

@@ -1,7 +1,9 @@
 {
   "origin": {
     "name": "egg-reconstruction",
-    "source": "https://github.com/facebookresearch/EGG"
+    "source": "https://github.com/facebookresearch/EGG",
+    "upstream_source": "https://github.com/facebookresearch/EGG",
+    "paper": null
   },
   "system": {
     "game_type": "signalling",

systems/nav-to-center/metadata.yml

@@ -1,6 +1,7 @@
 origin:
   name: nav-to-center
   source: https://github.com/brendon-boldt/filex-emergent-language
+  upstream_source: https://github.com/brendon-boldt/filex-emergent-language
   paper: https://openreview.net/forum?id=49A1Y6tRhaq
 system:
   game_type: navigation

systems/nav-to-center/system.json

@@ -2,6 +2,7 @@
   "origin": {
     "name": "nav-to-center",
     "source": "https://github.com/brendon-boldt/filex-emergent-language",
+    "upstream_source": "https://github.com/brendon-boldt/filex-emergent-language",
     "paper": "https://openreview.net/forum?id=49A1Y6tRhaq"
   },
   "system": {