Update dependency on ducc0 to 0.8.0

[ziotom78]

This PR updates ducc0 to version 0.8.0, which enables the use of the DUCC0_OPTIMIZATION variable. This should permit to overcome the problems described in issue #91.

[ziotom78]

The tests ran by .github/workflows/tests.yml now take 1m30s instead of 2m40s to run: impressive!

[ziotom78]

Ok, the documentation on Readthedocs has been built successfully (build #12798035). It completed successfully in 310 seconds: do you think this might fix #90?

[mreineck]

The tests ran by .github/workflows/tests.yml now take 1m30s instead of 2m40s to run: impressive!

As long as the test cases themselves are very small, this is expected, since the compile time dominates. For a large test suite with demanding tests (e.g. the one coming with ducc0), the testing time will become much longer when optimization is switched off.

It completed successfully in 310 seconds: do you think this might fix #90?

If it is a matter of memory consumed by the compiler, I'm pretty sure it will.