Added parallel testing for GitHub actions

docker/8.3/supervisord.conf

@@ -0,0 +1,14 @@
+[supervisord]
+nodaemon=true
+user=root
+logfile=/var/log/supervisor/supervisord.log
+pidfile=/var/run/supervisord.pid
+
+[program:php]
+command=%(ENV_SUPERVISOR_PHP_COMMAND)s
+user=%(ENV_SUPERVISOR_PHP_USER)s
+environment=LARAVEL_SAIL="1"
+stdout_logfile=/dev/stdout
+stdout_logfile_maxbytes=0
+stderr_logfile=/dev/stderr
+stderr_logfile_maxbytes=0