Test v2 in CI as it's being developed

[BooleanCat]

Please provide a brief description of the change.

Create a stub directory for building v2 using rangefunc to check that CI works as expected.

Which issue does this change relate to?

N/A.

Contribution checklist.

Replace the space in each box with "X" to check it off.

• [x] I have read and understood the CONTRIBUTING guidelines
• [x] My code is formatted (make check)
• [x] I have run tests (make test)
• [x] All commits in my PR conform to the commit hygiene section
• [x] I have added relevant tests
• [x] I have not added any dependencies

Additional context

Add any other context about the problem here.

[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Comparison is base (3fbdd2f) 100.00% compared to head (f1f4863) 100.00%.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #97 +/- ## ========================================= Coverage 100.00% 100.00% ========================================= Files 24 24 Lines 630 630 ========================================= Hits 630 630 ```

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