v1.7.0-alpha

knotserver: * rework Branches and Tags endpoint to use `git for-each-ref`. this is far more performant that go-git's reference iterator, and it is not susceptible to the infamous map-write-while-read bug on larger repos. * emit language breakdown information in gitRefUpdate, this allows appviews to update their knowledge of a repo language more often. * improved error handling in knotserver/internal. it should now be easier to debug failed hooks or pipeline events.