feat: add terraform workspace segment

[matsest]

Prerequisites

• I have read and understand the CONTRIBUTING guide
• The commit message follows the conventional commits guidelines
• Tests for the changes have been added (for bug fixes / features)
• Docs have been added / updated (for bug fixes / features)

Description

This adds support for showing the current terraform workspace name.

Inspired by a bash prompt I've used to show the current workspace:

function terraform_prompt()
  {
     if [ -d .terraform ]; then
       workspace="$(command terraform workspace show 2>/dev/null)"
       echo " (${workspace})"
     fi
  }

[matsest]

The existence of the .terraform dir and test for it is the WIP part I've identified and not too sure about (not very familiar with golang)

Edit: I think this is working now, after testing locally and running the gh actions. But very open to improvement suggestions :)

[JanDeDobbeleer]

@matsest feel free to reach out for help when you need it, I'm here to assist. Great work overall, looking forward to merging this 👍🏻

[JanDeDobbeleer]

2 comments and a general remark, can you squash all these commits into 1? It's small enough to be in a single commit context.

[matsest]

@JanDeDobbeleer Sounds good! Will fix this when I'm back home tomorrow evening

[matsest]

Thanks for the helpful review. I've gone through your review comments, rebased and squashed the PR into one commit. Hope it looks good now @JanDeDobbeleer :)

[JanDeDobbeleer]

Hope it looks good now

Only need to remove the properties in the docs and it can be merged!