Add repo key for frr packages

Related-PRODX: PRODX-34894
Change-Id: Ie1e203450e66ab15c0340e0290e603068f9550fe
diff --git a/de/heat-templates/scripts/instance_boot.sh b/de/heat-templates/scripts/instance_boot.sh
index 5ddaae8..a212b5f 100644
--- a/de/heat-templates/scripts/instance_boot.sh
+++ b/de/heat-templates/scripts/instance_boot.sh
@@ -950,6 +950,7 @@
 function install_frr {
     function _install_frr_packages {
         FRRVER="frr-stable"
+        curl -s https://mirror.mirantis.com/.snapshots/frr-stable-latest/keys.asc | sudo apt-key add -
         add-apt-repository "deb [arch=amd64] https://mirror.mirantis.com/.snapshots/frr-stable-latest/ ${OS_CODENAME} ${FRRVER}"
         install_pkgs frr frr-pythontools
     }