Change to accept multi-pem blocks

[endzyme]

The API appears to accept the certificate as well as the intermediary certificates.

See #468

[smaeda-ks]

Thanks @endzyme
Could you also update the documentation page as well?
https://github.com/fastly/terraform-provider-fastly#building-the-documentation

Or, we will push a commit to your branch.

[smaeda-ks]

Thanks for adding the doc change! @endzyme

@Integralist
Could you please approve? This looks good to me.

Thanks

[endzyme]

Thanks @smaeda-ks! Any news on when we can expect this to be released?

[smaeda-ks]

To be clear: #468 is already addressed in our system so you no longer need to upload the full chain for the LE certs. Given that, there's no urgency at this moment, and we will be releasing a new version after #467 is merged. Maybe sometime next week.

[endzyme]

Thanks again for the diligence and attention getting this through!