The released gh-md-toc.linux.amd64.tgz prints http headers

[developerdong]

Describe the bug
I download the latest release from https://github.com/ekalinin/github-markdown-toc.go/releases/download/1.2.0/gh-md-toc.linux.amd64.tgz. When I execute it, it prints not only toc to my console, but also some header strings like this.

Table of Contents
=================

Header: X-Commonmarker-Version=0.21.0
Header: X-Frame-Options=deny
Header: Referrer-Policy=origin-when-cross-origin, strict-origin-when-cross-origin
Header: Server=GitHub.com
Header: X-Ratelimit-Limit=60
Header: X-Content-Type-Options=nosniff
Header: X-Xss-Protection=0
Header: X-Ratelimit-Remaining=37
Header: Access-Control-Allow-Origin=*
Header: Content-Security-Policy=default-src 'none'
Header: Access-Control-Expose-Headers=ETag, Link, Location, Retry-After, X-GitHub-OTP, X-RateLimit-Limit, X-RateLimit-Remaining, X-RateLimit-Used, X-RateLimit-Resource, X-RateLimit-Reset, X-OAuth-Scopes, X-Accepted-OAuth-Scopes, X-Poll-Interval, X-GitHub-Media-Type, Deprecation, Sunset
Header: Strict-Transport-Security=max-age=31536000; includeSubdomains; preload
Header: Vary=Accept-Encoding, Accept, X-Requested-With
Header: Date=Wed, 07 Jul 2021 12:41:49 GMT
Header: Content-Type=text/html;charset=utf-8
Header: X-Ratelimit-Reset=1625662491
Header: X-Ratelimit-Used=23
Header: X-Ratelimit-Resource=core
Header: X-Github-Request-Id=83A2:32F4:3A83D97:6ECFA15:60E5A10C
* [heading1](#heading1)

Created by [gh-md-toc](https://github.com/ekalinin/github-markdown-toc.go)

But when I use the binary executable file built from the source by myself, it prints correctly without the headers.

To Reproduce

1. Download the binary file from https://github.com/ekalinin/github-markdown-toc.go/releases/download/1.2.0/gh-md-toc.linux.amd64.tgz
2. Extract the tar ball
3. Execute the binary file gh-md-toc path/to/the/readme/file

Expected behavior
Do not print the headers.

Environment (please complete the following information):

• OS: Ubuntu
• Version 20.04.1 LTS with kernel 5.4.0-73-generic

Additional context
None.