Add Updates definition file

Author: mominul

UPDATES.json

@@ -0,0 +1,10 @@
+{
+    "updates": {
+      "linux": {
+        "open-url": "https://github.com/OpenBangla/OpenBangla-Keyboard/releases",
+        "latest-version": "1.4.0",
+        "download-url": "https://github.com/OpenBangla/OpenBangla-Keyboard/releases",
+        "changelog": ""
+      }
+    }
+  }