updated postgresssql repos url to fix main verify issue

Signed-off-by: muthuja <muthujabavaji.vempalli@progress.com>

scripts/bk_tests/bk_install.sh

@@ -9,7 +9,7 @@ set -e
 # The fix:
 # 1. Add `deb https://apt-archive.postgresql.org/pub/repos/apt bionic-pgdg main` to sources.list
 # 2. Remove /etc/apt/sources.list.d/pgdg.list
-sudo echo "deb https://apt-archive.postgresql.org/pub/repos/apt bionic-pgdg main">>/etc/apt/sources.list
+sudo echo "deb https://apt.postgresql.org/pub/repos/apt/ focal-pgdg main 13">>/etc/apt/sources.list
 rm /etc/apt/sources.list.d/pgdg.list
 
 echo "Removing postgresql-9.3"