fix: renamed requirements to dependencies to match Helm standards

[cebidhem]

Signed-off-by: cebidhem [email protected]

Fixes https://github.com/norwoodj/helm-docs/issues/88

This PR introduces a breaking change, as it changes the template's key to generate documentation about the sub-charts / dependencies. Indeed, I assumed it was unnecessary to add a feature flag for this, given the low criticality it can go in a helm-docs v2.

However, I kept the compatibility with Helm v1 and the requirements.txt file.

All tests have passed.

[norwoodj]

You need to resolve conflicts. I also think we may need to wait on this for a v2, as it's a breaking change. But I like the idea