New version of bst can not use repo that has had workspaces

Summary

If a old workspace exists or has existed then bst build and bst workspace list both fail but do not say which work space has failed or where it is located.

What is the current bug behavior?

Message saying workspace uses too older format

What is the expected correct behavior?

Message saying which workspace(s) uses too older format.

In the case were no workspace exists then bst could safely just update or remove the file.

Steps to reprocuce

create a .bst/workspaces.yml file with the following content

format-version: 3
workspaces: {}

Relevant logs and/or screenshots

(venvbuildstream) [will@wsx280 freedesktop-sdk]$ bst workspace list

Error loading project: Workspace configuration format version 3 not supported.Please recreate this workspace.
[--:--:--][        ][    main:core activity                 ] START   Terminating buildbox-casd
[--:--:--][        ][    main:core activity                 ] WARNING Buildbox-casd didn't exit in time and has been killed
[00:00:15][        ][    main:core activity                 ] SUCCESS Terminating buildbox-casd
(venvbuildstream) [will@wsx280 freedesktop-sdk]$
Edited by William Salmon