Backport of add build support script to print out the submodule versions required in other submodules into release/1.18.x

[jmurret]

Backport

This PR is manual from #21635.

The below text is copied from the body of the original PR.

---

Description

This is used during releases to know which bumps need to be made. Will manually backport to 1.15, 1.17, and 1.18.

Usage:

$ ./build-support/scripts/consul-module-versions-in-consul.sh
Module versions for directory: '.':
--------------
github.com/hashicorp/consul/api v1.29.1 => ./api
add build support script to print out the submodule versions required in other submodules
github.com/hashicorp/consul/envoyextensions v0.7.0 => ./envoyextensions
github.com/hashicorp/consul/proto-public v0.6.1 => ./proto-public
github.com/hashicorp/consul/sdk v0.16.1 => ./sdk
github.com/hashicorp/consul/troubleshoot v0.6.1 => ./troubleshoot
--------------

Module versions for directory: 'api':
--------------
github.com/hashicorp/consul/api
github.com/hashicorp/consul/proto-public v0.6.1 => ../proto-public
github.com/hashicorp/consul/sdk v0.16.1 => ../sdk
--------------

Module versions for directory: 'envoyextensions':
--------------
github.com/hashicorp/consul/envoyextensions
github.com/hashicorp/consul/api v1.29.1 => ../api
github.com/hashicorp/consul/proto-public v0.6.1 => ../proto-public
github.com/hashicorp/consul/sdk v0.16.1 => ../sdk
--------------

Module versions for directory: 'proto-public':
--------------
github.com/hashicorp/consul/proto-public
--------------

Module versions for directory: 'sdk':
--------------
github.com/hashicorp/consul/sdk
--------------

Module versions for directory: 'troubleshoot':
--------------
github.com/hashicorp/consul/troubleshoot
github.com/hashicorp/consul/api v1.29.1 => ../api
github.com/hashicorp/consul/envoyextensions v0.7.0 => ../envoyextensions
github.com/hashicorp/consul/proto-public v0.6.1 => ../proto-public
github.com/hashicorp/consul/sdk v0.16.1 => ../sdk
--------------

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Overview of commits

• 7a0d3ca - 2ae8013