test: Set stop_signal to SIGTERM

The official nginx images set STOPSIGNAL to SIGQUIT which dumps core.
Set it to SIGTERM to avoid dumping core on e2e tests.

Signed-off-by: Ricardo Branco <rbranco@suse.de>

Author: ricardobranco777

pkg/e2e/fixtures/dependencies/recreate-no-deps.yaml

@@ -9,6 +9,7 @@ services:
 
   nginx:
     image: nginx:alpine
+    stop_signal: SIGTERM
     healthcheck:
       test:     "echo | nc -w 5 localhost:80"
       interval: 2s

pkg/e2e/fixtures/restart-test/compose-depends-on.yaml

@@ -3,20 +3,23 @@ services:
     image: nginx:alpine
     init: true
     command: tail -f /dev/null
+    stop_signal: SIGTERM
     depends_on:
       nginx: {condition: service_healthy, restart: true}
 
   no-restart:
     image: nginx:alpine
     init: true
     command: tail -f /dev/null
+    stop_signal: SIGTERM
     depends_on:
       nginx: { condition: service_healthy }
 
   nginx:
     image: nginx:alpine
     labels:
       TEST: ${LABEL:-test}
+    stop_signal: SIGTERM
     healthcheck:
       test:     "echo | nc -w 5 localhost:80"
       interval: 2s