How to download a file from GitHub Enterprise using Terraform?

Here is my s3_policy.json

{
  "Version":"2012-10-17",
  "Statement":[
    {
      "Sid":"mybucket",
      "Effect":"Allow",
      "Principal": "*",
      "Action":["s3:GetObject"],
      "Resource":[
        "arn:aws:s3:::${bucket_name}/*"
      ],
      "Condition": {
          "IpAddress": {
              "aws:SourceIp": [
              "10.xx.xxx.x",
              "172.168.xx.x",
              ........,
              .........,
              ..........,
              ...........,
              ]
          }
      }
    }
  ]
}

I have common repo which I use it for different projects. This common repo has a CIDR IP list in yaml format.

I would like to pull it into my Terraform project so that I can re use the same file instead of hardcoding IP addresses.

I'm unable to figure out a way to automate this instead of hardcoding IP addresses in this repo.