chore: bump dependencies

[barnabasbusa]

Bumping dependencies, so we can avoid errors like these:

SIGSEGV: segmentation violation
    PC=0x478de8 m=0 sigcode=1 addr=0xffff8efc6ba0

    goroutine 0 gp=0xa3c2e0 m=0 mp=0xa3cf80 [idle]:
    runtime.systemstack(0x47d75f)
            /usr/local/go/src/runtime/asm_amd64.s:514 +0x48 fp=0x5554fffff938 sp=0x5554fffff928 pc=0x478de8

    goroutine 178 gp=0xc000324700 m=0 mp=0xa3cf80 [running]:
    runtime.systemstack_switch()
            /usr/local/go/src/runtime/asm_amd64.s:479 +0x8 fp=0xc0003e1980 sp=0xc0003e1970 pc=0x478d88
    runtime.persistentalloc(0x0?, 0x0?, 0xa0000000?)
            /usr/local/go/src/runtime/malloc.go:1921 +0x45 fp=0xc0003e19c8 sp=0xc0003e1980 pc=0x41c2a5
    runtime.(*spanSet).push(0xa56680, 0x7fffffd9aaf0)
            /usr/local/go/src/runtime/mspanset.go:104 +0xcb fp=0xc0003e1a30 sp=0xc0003e19c8 pc=0x43b14b
    runtime.(*mcentral).uncacheSpan(0x1aa52b3d3a893a43?, 0xfe56834a79ef26be?)
            /usr/local/go/src/runtime/mcentral.go:244 +0x85 fp=0xc0003e1a58 sp=0xc0003e1a30 pc=0x41f105
    runtime.(*mcache).refill(0x7fffffd8e5c0, 0xd)
            /usr/local/go/src/runtime/mcache.go:160 +0x9f fp=0xc0003e1a98 sp=0xc0003e1a58 pc=0x41e59f
    runtime.(*mcache).nextFree(0x7fffffd8e5c0, 0xd)
            /usr/local/go/src/runtime/malloc.go:964 +0x85 fp=0xc0003e1ad0 sp=0xc0003e1a98 pc=0x41ac65
    runtime.mallocgcSmallNoscan(0x0?, 0x1?, 0x67?)
            /usr/local/go/src/runtime/malloc.go:1283 +0x195 fp=0xc0003e1b28 sp=0xc0003e1ad0 pc=0x41b255
    runtime.mallocgc(0x40, 0x0, 0x0)
            /usr/local/go/src/runtime/malloc.go:1055 +0xb9 fp=0xc0003e1b58 sp=0xc0003e1b28 pc=0x471b79
    runtime.growslice(0xc000582d40, 0x1?, 0x6f808417dedac99f?, 0xf5ddfd4dfad45387?, 0x71c53bf8bdc2f735?)
            /usr/local/go/src/runtime/slice.go:264 +0x5c9 fp=0xc0003e1bc8 sp=0xc0003e1b58 pc=0x475e49
    github.com/wealdtech/go-eth2-util.hkdfModR({0xc000582d40, 0x20, 0x20}, {0x0, 0x0})
            /go/pkg/mod/github.com/wealdtech/go-eth2-util@v1.6.4/crypto.go:156 +0x2f9 fp=0xc0003e1d40 sp=0xc0003e1bc8 pc=0x667279
    github.com/wealdtech/go-eth2-util.DeriveChildSK(0xc0000b435a?, 0x1?)
            /go/pkg/mod/github.com/wealdtech/go-eth2-util@v1.6.4/crypto.go:103 +0x2f fp=0xc0003e1d78 sp=0xc0003e1d40 pc=0x6667cf
    github.com/wealdtech/go-eth2-util.PrivateKeyFromSeedAndPath({0xc0000f4040, 0x40, 0x40}, {0xc0000b4348?, 0x1?})
            /go/pkg/mod/github.com/wealdtech/go-eth2-util@v1.6.4/crypto.go:72 +0x245 fp=0xc0003e1e48 sp=0xc0003e1d78 pc=0x666385
    main.selectVals.func1()
            /go/pkg/mod/github.com/protolambda/eth2-val-tools@v0.1.1/main.go:415 +0xdd fp=0xc0003e1f78 sp=0xc0003e1e48 pc=0x66afbd
    golang.org/x/sync/errgroup.(*Group).Go.func1()
            /go/pkg/mod/golang.org/x/sync@v0.0.0-20190423024810-112230192c58/errgroup/errgroup.go:57 +0x56 fp=0xc0003e1fe0 sp=0xc0003e1f78 pc=0x6677d6
    runtime.goexit({})
            /usr/local/go/src/runtime/asm_amd64.s:1700 +0x1 fp=0xc0003e1fe8 sp=0xc0003e1fe0 pc=0x47ada1
    created by golang.org/x/sync/errgroup.(*Group).Go in goroutine 1
            /go/pkg/mod/golang.org/x/sync@v0.0.0-20190423024810-112230192c58/errgroup/errgroup.go:54 +0x76