Update docs version tag
Follow-up for !89 (merged) which also sets v0.3.0 in the NEWS file.
(I couldn't spot any more old v0.2.0 tags in the repo with grep.)
Follow-up for !89 (merged) which also sets v0.3.0 in the NEWS file.
(I couldn't spot any more old v0.2.0 tags in the repo with grep.)