Update Example (Shell Script) (#4895)

"read ARGS" does not work for web action, this is modified with "ARGS=$@".
diff --git a/docs/actions-docker.md b/docs/actions-docker.md
index e078d93..4e35b82 100644
--- a/docs/actions-docker.md
+++ b/docs/actions-docker.md
@@ -230,7 +230,7 @@
 
 ```
 #!/bin/bash
-read ARGS
+ARGS=$@
 NAME=`echo "$ARGS" | jq -r '."name"'`
 DATE=`date`
 echo "{ \"message\": \"Hello $NAME! It is $DATE.\" }"