Add Information to CONTRIBUTING.md about JHipster Snapshot Versions

[SudharakaP]

Overview of the issue

It's my understanding that if we are using a snapshot dependency version we have to build the jhipster/jhipster project so that the generator correctly points to the snapshot. I suggest adding this information to the CONTRIBUTING.md especially for new users who are setting up their development environment for the first time.

Motivation for or Use Case

Save development time and ease of quickly setting up the dev environment for new users.

Reproduce the error

Change the jhipster-dependencies.version line in pom.xml.ejs to a snapshot version (if it's not already on a snapshot version), remove the contents of the .m2 directory and try to generate and build a project using the generator.

Related issues

#9571

Suggest a Fix

Add a note to the CONTRIBUTING.md file about cloning the jhipster/jhipster project and building it in case of snapshot release.

• Checking this box is mandatory (this is just to show you read everything)