* feat(config): add support for token helper
Use the new interface in `pnpm/credentials-by-uri` for supporting token
helpers. A token helper is an executable, set in the user's `.npmrc`
which outputs an auth token. This can be used in situations where the
`authToken` is not a constant value, but is something that refreshes
regularly, where a script or other tool can use an existing refresh
token to obtain a new access token.
The configuration for the path to the helper must be an absolute path,
with no arguments. In order to be secure, it is _only_ permitted to set
this value in the user `.npmrc`, otherwise a project could place a value
in a project local `.npmrc` and run arbitrary executables.
A similar feature is available in many similar tools. The implementation
in `credentials-by-uri` is modelled after the `vault` (vaultproject.io)
implementation - https://github.com/hashicorp/vault/blob/main/command/token/helper_external.go
* test: fix
* docs: add changesets
Co-authored-by: Zoltan Kochan <z@kochan.io>
