fix #16 lock jup-ag/core to v 1.0.0-beta.28

Author: pmioduszewski

package.json

@@ -21,7 +21,7 @@
 		"./src/generator.js"
 	],
 	"dependencies": {
-		"@jup-ag/core": "^1.0.0-beta.28",
+		"@jup-ag/core": "1.0.0-beta.28",
 		"@solana/web3.js": "^1.44.0",
 		"asciichart": "^1.5.25",
 		"axios": "^0.27.2",