[PLAT-15322] Make sure build files have fresh last_modified date to m…

…ake sure Play Framework assets caching works as expected

Summary:
Play Framework sets ETag header for caching based on static resource last modified date.
Currently, last modified date for our assets is always set at Jan 1, 2010 - which makes YBA UI to break after YBA upgrades.
The reason is that browser is trying to use old index.html pagem which links to missing js files (js file names are generated somehow by UI build and is changing).
This diff sets the environment variable, which sets file modification dates inside the build to a fresh timestamp.
This will make sure browser downloads all the resources once after YBA upgrade and continue caching these after..

Test Plan: Built YBA package with yb_release. Made sure web asset files have the right last_modified date.

Reviewers: nsingh, sanketh, rmadhavan

Reviewed By: rmadhavan

Subscribers: yugaware

Differential Revision: https://phorge.dev.yugabyte.com/D38063

managed/yb_release

@@ -14,6 +14,7 @@ fi
 set -euo pipefail
 
 export DEVOPS_HOME="${BASH_SOURCE%/*}"/devops
+export SOURCE_DATE_EPOCH="$(date +%s)"
 
 . "$DEVOPS_HOME/bin/"/common.sh