[jkomalley]

Passing --use-lxd now runs the build in managed mode even when CRAFT_BUILD_ENVIRONMENT=host is set. I added the check to _use_provider, updated/added to the parameters for the existing _use_provider tests, and added a little blurb about it to the docs.

Fixes #354

---

• I've followed the contribution guidelines.
• I've signed the CLA.
• I've successfully run make lint && make test.
• I've added or updated any relevant documentation.
• In documents I changed, I added a meta description if one was missing.
• I've updated the relevant release notes.

[lengau]

Thanks!

[jahn-junior]

Thanks for the contribution! (and bonus points for adding a meta description)

I left a few minor wording suggestions for the docs changes, but that should be all before this is ready for merge.

[lengau]

Bypassing flaky test failure (each spread test did succeed, though not all together).

Thanks again @jkomalley !