content/about: note former Prometheus team affiliation
content/about: note former Prometheus team affiliation

Signed-off-by: Matt Layher <76528ff2e917253aa2211f68e4ca60b5b846dcf5@gmail.com>

mdlayher/mdlayher.com,mdlayher/mdlayher.com,mdlayher/mdlayher.com