Fixed do500-toolbox URL. Changed to quay.io/redhat

Ravi Srinivasan

2019-02-06 313b8896df9370d28be45ea790902b0330f12e29

 exercises/2-attack-of-the-pipelines/README.md

@@ -199,7 +199,7 @@
</p>

```bash
docker run -it -v C:/do500-workspace:/home/tool-box/workarea:Z quay.io/jrigsbee/do500-toolbox /bin/bash
docker run -it -v C:/do500-workspace:/home/tool-box/workarea:Z quay.io/redhat/do500-toolbox /bin/bash
```

```bash