Update build script

[rohan-goel]

Fixes

Fixes #287 by @obulat

Description

Added shx package and update build script.
Able to test build on cross platform.

Technical details

Tests

Screenshots

Checklist

• My pull request has a descriptive title (not a vague title like Update index.md).
• My pull request targets the default branch of the repository (main or master).
• My commit messages follow best practices.
• My code follows the established code style of the repository.
• I added tests for the changes I made (if applicable).
• I added or updated documentation (if applicable).
• I tried running the project locally and verified that there are no
  visible errors.

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[obulat]

Thank you for your contribution, @rohan-goel !
I tested it on Windows and Ubuntu (Windows Subsystem for Linux), and it works. The only small change I added was to add shx before echo, too. Without it, CNAME was saved with a 'crlf' line ending on Windows.