First: your repository url is https://github.com/rcbandit111/terraform_helm_chart_poc (and NOT https://github.com/rcbandit111/terraform_helm_chart_poc/tree/main/helm/spring-helm-stg)
After fixing that, you should then place the index.yaml file at root level (instead of helm directory) and also – make it a valid one. That’s also “kind of” important.
Because your repository is filled with sub-directories, lots of index files and seems pretty messed-up (it’s OK to make experiments… it’s also OK to delete irrelevant parts) you may consider rearranging everything in a new branch and merge it to master OR create a new better-organized repository.
RESPECT to @marko for the documentation link in the comment. Please use that when you are writing your repository’s index file
Cheers
solved index.yaml : 404 Not Found