update package.json based on npm auto-correction hint

Author: zbryikt

package.json

@@ -13,7 +13,7 @@
   ],
   "repository": {
     "type": "git",
-    "url": "https://github.com/plotdb/sheet"
+    "url": "git+https://github.com/plotdb/sheet.git"
   },
   "engines": {
     "node": ">=10.14.1",