Rotate Habitat Builder's SSL certificates

Chef Habitat On-Prem Builder’s web frontend runs on NGINX using the habitat/builder-api-proxy service. The NGINX config for this service loads the SSL certificate and key from /hab/svc/builder-api-proxy/files.

Rotate the SSL certificate and key

There’s really a few simple commands to run in order to rotate your key.

Rename your SSL certificate and key file to the names required by the builder-api-proxy service:
```
cp <CERTIFICATE_CHAIN_FILENAME> ssl-certificate.crt
cp <CERTIFICATE_KEY_FILENAME> ssl-certificate.key
```
The certificate and key files must be named ssl-certificate.crt and ssl-certificate.key.

Upload the certificate and key files to the builder service:

hab file upload "builder-api-proxy.default" "$(date +%s)" ./ssl-certificate.crt
hab file upload "builder-api-proxy.default" "$(date +%s)" ./ssl-certificate.key

Restart the builder-api-proxy service:
```
hab svc stop habitat/builder-api-proxy && hab svc start habitat/builder-api-proxy
```
This puts the updated files into the appropriate path and restarts NGINX so that it’s using your new certificate and key.

You should now be able to verify through your browser or with the openssl s_client -connect command that Habitat Builder has an updated certificate.