Fix cli format flag fallback

[xoxys]

While repo ls --format flag is deprecated, we added fallback code to not break it. However, the fallback was not working properly as the --format template was evaluated per item in slice while --output is not.

This PR ensures the --format fallback wraps the given template in a range loop.

Now using the format flag is working again:

❯ ../../golang/woodpecker/woodpecker/dist/woodpecker-cli repo ls --format="{{ .FullName }} {{ .Name }}"
11:09PM WRN the --format flag is deprecated, please use --output instead
woodpecker-ci/foo foo
test/repo repo

[woodpecker-bot]

Deployment of preview was torn down