fix(images): use new runner install location (#1628)

images/start-runner.sh

@@ -1,9 +1,9 @@
 #!/bin/bash -e
 exec > >(tee /var/log/runner-startup.log | logger -t user-data -s 2>/dev/console) 2>&1
 
-cd /home/ec2-user/actions-runner
+cd /opt/actions-runner
 
 ## This wrapper file re-uses scripts in the /modules/runners/templates directory
 ## of this repo. These are the same that are used by the user_data functionality 
 ## to bootstrap the instance if it is started from an existing AMI.
-${start_runner}
+${start_runner}