Replace alpine with ubuntu as base image in the Dockerfile (#31)

Part of [Create a public laconicd testnet](https://www.notion.so/Create-a-public-laconicd-testnet-896a11bdd8094eff8f1b49c0be0ca3b8)

Co-authored-by: Nabarun <nabarun@deepstacksoft.com>
Reviewed-on: cerc-io/laconic2d#31
Co-authored-by: Prathamesh Musale <prathamesh.musale0@gmail.com>
Co-committed-by: Prathamesh Musale <prathamesh.musale0@gmail.com>

tests/sdk_tests/docker-compose.yml

@@ -2,7 +2,7 @@ services:
   laconicd:
     restart: unless-stopped
     image: cerc/laconicd:local
-    entrypoint: ["sh", "/docker-entrypoint-scripts.d/create-fixturenet.sh"]
+    entrypoint: ["bash", "/docker-entrypoint-scripts.d/create-fixturenet.sh"]
     environment:
       - TEST_AUCTION_ENABLED
       - TEST_REGISTRY_EXPIRY