pidgin/nest

Run update-lastmod script while building container image

This will make sure that the creation date and last modified date of each markdown file matches to what the repository history says

Testing Done:
Built container image and verified the added script was indeed getting triggered.
Verified that the script was actually modified the markdown files with the correct creation and last updated date.

Bugs closed: NEST-44

Reviewed at https://reviews.imfreedom.org/r/521/
Alan Hoskins <alanhoskins@gmail.com>
Elliott Sales de Andrade <quantum.analyst@gmail.com>
Frederick F. Kautz IV <fkautz@alumni.cmu.edu>
Gary Kramlich <grim@reaperworld.com>
Harrison <harrisonhopkins@gmail.com>
Jason Allan <code@jasonderrythomas.com>
John Bailey <rekkanoryo@rekkanoryo.org>
Richard Laager <rlaager@wiktel.com>
Robert Vehse <robertvehse@fastmail.fm>
Sorvival <sorvival@tutanota.com>
Zero <programmingzero@gmail.com>