Use postinstall script

Use postinstall script as this should be supported by yarn.

Author: nkuba

package.json

@@ -24,7 +24,7 @@
     "test": "hardhat test",
     "test:system": "NODE_ENV=system-test hardhat test ./test/system/*.test.js",
     "prepublishOnly": "./scripts/prepare-artifacts.sh --network $npm_config_network",
-    "prepare": "tsc -p tsconfig.export.json"
+    "postinstall": "tsc -p tsconfig.export.json"
   },
   "devDependencies": {
     "@keep-network/hardhat-helpers": "^0.4.1-pre.2",