Some features do not work after GitLab version 13.5.
This update alerts the user that they are using an outdated
version.

Resolve "Warn users that they should use supported GitLab version"

See merge request gitlab-org/gitlab-vscode-extension!252

fix(readme): correct link to PAT settings

See merge request gitlab-org/gitlab-vscode-extension!278

fix(welcome screen): update link to personal access token settings

See merge request !282

chore(ci variables): update the ci_variables.json

See merge request !283

docs: maintainer documentation

See merge request !281