Add CI for building docker image (#4)

Part of https://www.notion.so/Implement-stacks-1b5a6b22d472806a82f5dafed6955138

Reviewed-on: LaconicNetwork/zenith-wallet-web#4
Co-authored-by: Nabarun <nabarun@deepstacksoft.com>
Co-committed-by: Nabarun <nabarun@deepstacksoft.com>

.gitea/workflows/lint-and-build.yml

@@ -2,7 +2,7 @@ name: Lint and Build
 
 on:
   pull_request:
-    branches: [ main, milestone-3 ]
+    branches: [ main ]
 
 jobs:
   lint-and-build: