Run update-lastmod script while building container image

Review Request #521 — Created Feb. 18, 2021 and submitted — Latest diff uploaded

Information

pidgin/nest
default
fe476cce1682

Reviewers

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

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.