docs(readme): update time format for markdown parser
docs(readme): update time format for markdown parser

Closes #246
googlecodelabs/tools,Qwiklabs/codelab-tools,Qwiklabs/codelab-tools,Qwiklabs/codelab-tools,googlecodelabs/tools,googlecodelabs/tools,googlecodelabs/tools,Qwiklabs/codelab-tools