fix(cd): replace heredoc with printf to avoid YAML parse error

Unindented heredoc content inside a YAML literal block breaks parsing.
Gitea silently drops workflows with YAML errors, causing the CD job
to never trigger.

.gitea/workflows/cd.yml

@@ -49,11 +49,7 @@ jobs:
           mkdir -p ~/.ssh
           echo "${{ secrets.INFRA_DEPLOY_KEY }}" > ~/.ssh/infra_deploy_key
           chmod 600 ~/.ssh/infra_deploy_key
-          cat >> ~/.ssh/config << 'SSHEOF'
-Host gitea.d-ma.be
-  Port 30022
-  StrictHostKeyChecking no
-SSHEOF
+          printf 'Host gitea.d-ma.be\n  Port 30022\n  StrictHostKeyChecking no\n' >> ~/.ssh/config
 
           GIT_SSH_COMMAND="ssh -i ~/.ssh/infra_deploy_key -o IdentitiesOnly=yes" \
             git clone "${INFRA_REPO}" /tmp/infra-update