update dependencies ahead of v0.16.0-alpha.1
Signed-off-by: Daniel Martí <mvdan@mvdan.cc>
Change-Id: I77506ea43d3d775a33b44cfaf42f3ff92202e5d7
Reviewed-on: https://cue.gerrithub.io/c/cue-lang/cue/+/1229643
Reviewed-by: Matthew Sackman <matthew@cue.works>
TryBot-Result: CUEcueckoo <cueckoo@cuelang.org>
Unity-Result: CUE porcuepine <cue.porcuepine@gmail.com>