Update do v0.4.23

Release issue: https://github.com/ipfs/go-ipfs/issues/6837

Currently experiencing some `go fmt` errors during tests with `./core/coreapi/unixfs.go` 🤔

```log
go: finding github.com/mattn/go-runewidth v0.0.4
bin/test-go-fmt
Following Go code is not formatted.
-----------------------------------
./core/coreapi/unixfs.go
-----------------------------------
Run 'go fmt ./...' in your source directory
make: *** [mk/golang.mk:64: test_go_fmt] Error 1
The command '/bin/sh -c TEST_NO_FUSE=1 make test_short' returned a non-zero code: 2
```

Start by running `go fmt ./...` and `make test_short` with `TEST_NO_FUSE=1`, as shown in the issue. Inspect `./core/coreapi/unixfs.go` for formatting differences and confirm the release test no longer reports it as unformatted.

Written by the indexing model from the issue text.