Update mental.json (#239)

added linux release

plugins/mental.json

@@ -10,7 +10,11 @@
   "downloads": {
     "win": {
       "download": "https://github.com/Strum/Strums_Mental_VCV_Modules/releases/download/v0.5.b/mental-0.5.b-win.zip",
-      "sha256": "3d93d74cbbcd4899a367799f5803ed57c6d171f49e3062fe4c3dd8c932e00854"
+      "sha256": "3d93d74cbbcd4899a367799f5803ed57c6d171f49e3062fe4c3dd8c932e00854"      
+    },
+    "lin": {
+      "download": "https://github.com/Strum/Strums_Mental_VCV_Modules/releases/download/v0.5.b/mental-0.5.b-lin.zip",
+      "sha256": "e716ff6a9a98addc5eb07f92d8d524c627da5734375d97a084b8878a25b8f7c2"
     }
   }
 }