Am I doing this right?

Before I migrate my dev site to the main site I have to do a major WP update from 5.1 which I am advised to do manually. I need to block the search engines temporarily, I don’t want de-indexed during this process. With the current WP version my Customizr is not showing correctly. I have a file I created to put in the root directory for users and the search engines. Could someone take a look and tell me if I did this right? Please. I have php inside html.
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