adds update utils

[tarunKoyalwar]

Proposed Changes

• Implements new logic selfupdate logic based on nuclei update feature
• uses https://github.com/minio/selfupdate which only replaces the running process binary and not others (does not use lookPath etc instead uses syscalls). Ref:https://github.com/minio/selfupdate/tree/master/internal/osext
• Implements generic update/download logic so that this can be reused in pdtm
• Adds GetUpdateToolCallback , GetVersionCheckCallback to update and version check
• during self-update (upgrading) release notes of latest release are rendered and printed to stdout
• closes add utils to update app from gh releases #100
• poc available in adds version check and optional self update in tlsx tlsx#197