qtest: bump prom-env-test timeout to 6 minutes

The prom-env-test can take more than 5 minutes in a --enable-debug
build on a loaded system. Bumping to 6 minutes will give more headroom.

Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
[thuth: Bump timeout to 6 minutes instead of 3]
Signed-off-by: Thomas Huth <thuth@redhat.com>
Message-Id: <20231215070357.10888-8-thuth@redhat.com>
Signed-off-by: Alex Bennée <alex.bennee@linaro.org>

tests/qtest/meson.build

@@ -5,6 +5,7 @@ slow_qtests = {
   'qom-test' : 900,
   'test-hmp' : 240,
   'pxe-test': 600,
+  'prom-env-test': 360,
 }
 
 qtests_generic = [