devel/awless: fix build on riscv64

Bump golang.org/x/sys dependency to a version new enough
to support riscv64. Add missing riscv64-specific bits to
github.com/boltdb/bolt dependency.

Sponsored by: Berliner Linux User Group e.V.
Obtained from: go.etcd.io/bbolt
Approved by: dmgk (maintainer)