[gatsby-source-wordpress] Add Node self-cert workaround to README (#6061)
[gatsby-source-wordpress] Add Node self-cert workaround to README (#6061)

* add syntax highlighting to php code blocks

* add node self-signed cert workaround

gatsbyjs/gatsby,0x80/gatsby,fk/gatsby,ChristopherBiscardi/gatsby,gatsbyjs/gatsby,gatsbyjs/gatsby,ChristopherBiscardi/gatsby,fk/gatsby,gatsbyjs/gatsby,ChristopherBiscardi/gatsby,0x80/gatsby,mingaldrichgan/gatsby,mingaldrichgan/gatsby,gatsbyjs/gatsby,mingaldrichgan/gatsby,ChristopherBiscardi/gatsby,gatsbyjs/gatsby,fk/gatsby,0x80/gatsby