Discovery and use of contribution guidelines could be improved

Creating a GDP PR today via github I came to realise discovery of the contribution guidelines and use of supporting scripts could be improved.

During my last PR it was mentioned that there was a script to support the creation of a submodule update. Where to find it?

The "Contribution" section of the project Readme.md points people towards the Maintainers file which describes a traditional patch process, although later links to a general Contribution wiki page that will allow you to find the GDP Contribution guidelines. It may be worth updating the gdp Readme.md to point instead at the contributing.md file and bringing the m-g-d maintainers file up to date.

Having now found mention of the git-submodule-bump script I couldn't get it to work. The guidelines provide no example of its use. Running it without any params returns:

-e Usage:

./git-submodule-bump COMMIT_SUMMARY

I added the submodule update to the git cache and ran the script with a commit summary message, but I got the error:

No module updated.

Of course you can figure out what the script is doing by picking it apart but it would be better if there were some basic notes on how it is supposed to be used.

These are two relatively minor points but would improve the GDP development usability.

EDIT: Acceptance Criteria

• Refer to the comment below