Add alpine 3.14.2 images

[gngeorgiev]

PR Summary

This PR adds preview and stable docker images based on alpine 3.14.2. The new tag is 3.14

PR Checklist

• PR has a meaningful title
  • Use the present tense and imperative mood when describing your changes
• Summarized changes
• Change is not breaking
• Make sure all Dockerfile, .sh, .ps1 and .psm1 files have the correct copyright header
• This PR is ready to merge and is not Work in Progress.
  • If the PR is work in progress, please add the prefix WIP: to the beginning of the title and remove the prefix when the PR is ready.
• Adds a new image or tag
  • alpine:3.14
• OR
  • Update README.powershellcommunity.md
  • Update vsts-ci.yml

[gngeorgiev]

@anamnavi @TravisEz13 CI is passing. This is the same as #575 ✌️

[TravisEz13]

It will probably be early November before these get released. Unless they manage to get into the release already in progress.

[TravisEz13]

and Thanks for the help!