Replace versioneer for setuptools-scm

[santisoler]

Description

The new setuptools-scm allows to obtain the Semver version of any library through VCS by just installing the setuptools-scm package through pip or conda and then adding some configuration lines on the files used to install the library. We were already doing the same thing through versioneer, although it needed us to copy and paste some large files that don't get automatic updates.

I've already experimented with the replacement on Harmonica, so please take a look at fatiando/harmonica#196 before implementing the same changes on every library.

We know that maintenance tasks are very demanding, so we don't expect a single person to tackle this issue by themselves. Any help is very welcomed, so please comment below that you want to take care of the changes on any repository and we will assign it to you.

Apply changes to

Libraries:

• [x] boule
• [ ] erizo
• [x] harmonica
• [x] pooch
• [ ] rockhound
• [x] verde
• [x] contributing

Further instructions

In order to solve this issue we need to start opening Pull Requests on each repository listed above. Optionally, we can open Issues on each repository if further discussion specific to that repository is needed.

Remember to mention this Issue on every Issue or Pull Request opened on each repository for keeping a record by adding something like:

Related to fatiando/maintenance#4

A quick checklist:

1. Open an Issue on each repository listed above (optional). Mention this Issue on them.
2. Open a Pull Request on the same repository to tackle the Issue. Mention this Issue on them.
3. Check-off the repository on the list above once the Pull Request is merged.
4. Close this issue when all items are checked-off.

[santisoler]

Worth looking at how @leouieda has solved this in pooch: https://github.com/fatiando/pooch/pull/235

[leouieda]

Basically done as well since erizo hasn't had any development and I'm not sure it will continue. Same for rockhound, which needs a complete rewrite.