Docs: update deploy script

deploy_docs.sh

 #!/bin/bash
 
 cd docs
-command -v greadlink 2>/dev/null 2>&1 || { echo >&2 "Command mkdocs not found. Are you in the right venv?"; exit 1; }
+command -v mkdocs 2>/dev/null 2>&1 || { echo >&2 "Command mkdocs not found. Are you in the right venv?"; exit 1; }
 mkdocs build
 rsync -auv ./site/* armadillica@flamenco.io:/home/armadillica/flamenco.io/docs