[BPK-2366] - Updated CONTRIBUTING.md with small troubleshooting step … (#1387)
[BPK-2366] - Updated CONTRIBUTING.md with small troubleshooting step … (#1387)

* [BPK-2366] - Updated CONTRIBUTING.md with small troubleshooting step when there are submodule issues

Skyscanner/backpack,Skyscanner/backpack,Skyscanner/backpack