Add destructive action warnings to SSL Endpoint commands
Update copy for certs:update
Fix specs + add new ones for confirmation
Merge pull request #900 from heroku/brandur-ssl-endpoint-destructive-actions

Add destructive action warnings to SSL Endpoint commands
Allow `--endpoint` option

This pull re-enables the `--endpoint` option available on select `certs`
commands which allows a customer with multiple endpoints to operate on
one in particular (this is now a legacy state). This help text is
required for the option parser to respect the particular option.
Add spec for endpoint-specific support
Merge pull request #899 from heroku/brandur-multi-endpoint

Allow `--endpoint` option
v2.41.0