Fix YAML alias-scanner crash: quote KEEPALIVED_PASSWORD/KEEPALIVED_VIRTUAL_IPS env values

mount-guard.py failed with "expected alphabetic or numeric character, but
found '*'" during rendering. Root cause: KEEPALIVED_PASSWORD and
KEEPALIVED_VIRTUAL_IPS were interpolated unquoted; when the live secret
value happens to start with '*', YAML's scanner parses it as an alias
reference (*anchor) instead of literal text. KEEPALIVED_UNICAST_PEERS on
the adjacent line was already quoted for the same reason (starts with
'#') - this brings the other two env values in line with that existing
convention. Also noted (not fixed here): live traefik-certs-dumper
service is running v2.10.0 while this file already pins v2.11.4 -
redeploy needed separately to pick that up.

traefik/traefik.yaml

@@ -5,8 +5,8 @@ services:
       KEEPALIVED_INTERFACE: eth0
       KEEPALIVED_PRIORITY: "150"
       KEEPALIVED_ROUTER_ID: "51"
-      KEEPALIVED_PASSWORD: ${KEEPALIVED_PASSWORD}
-      KEEPALIVED_VIRTUAL_IPS: ${KEEPALIVED_VIRTUAL_IPS}
+      KEEPALIVED_PASSWORD: "${KEEPALIVED_PASSWORD}"
+      KEEPALIVED_VIRTUAL_IPS: "${KEEPALIVED_VIRTUAL_IPS}"
       KEEPALIVED_UNICAST_PEERS: "#PYTHON2BASH:['192.168.4.31', '192.168.4.32']"
     command: --copy-service
     cap_add: [NET_ADMIN, NET_BROADCAST, NET_RAW]
@@ -39,8 +39,8 @@ services:
       KEEPALIVED_INTERFACE: eth0
       KEEPALIVED_PRIORITY: "100"
       KEEPALIVED_ROUTER_ID: "51"
-      KEEPALIVED_PASSWORD: ${KEEPALIVED_PASSWORD}
-      KEEPALIVED_VIRTUAL_IPS: ${KEEPALIVED_VIRTUAL_IPS}
+      KEEPALIVED_PASSWORD: "${KEEPALIVED_PASSWORD}"
+      KEEPALIVED_VIRTUAL_IPS: "${KEEPALIVED_VIRTUAL_IPS}"
       KEEPALIVED_UNICAST_PEERS: "#PYTHON2BASH:['192.168.4.32', '192.168.4.33']"
     cap_add: [NET_ADMIN, NET_BROADCAST, NET_RAW]
     networks: [host]