ci/lava: Fix shebang in deqp-runner.sh

Now, every rootfs based device has bash installed, so we can use bash
shebang instead of dash to enforce the use of bash's echo, not dash's
one.

Signed-off-by: Guilherme Gallo <guilherme.gallo@collabora.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/15938>

.gitlab-ci/deqp-runner.sh

@@ -1,4 +1,4 @@
-#!/bin/sh
+#!/bin/bash
 
 echo -e "\e[0Ksection_start:$(date +%s):test_setup[collapsed=true]\r\e[0Kpreparing test setup"