etcd: 3.1.6 -> 3.3.1

Semi-automatic update. These checks were performed:

- built on NixOS
- ran `/nix/store/bv1hwms0avpnxymgsvwyw9j3n8578k24-etcd-3.3.1-bin/bin/benchmark -h` got 0 exit code
- ran `/nix/store/bv1hwms0avpnxymgsvwyw9j3n8578k24-etcd-3.3.1-bin/bin/benchmark --help` got 0 exit code
- ran `/nix/store/bv1hwms0avpnxymgsvwyw9j3n8578k24-etcd-3.3.1-bin/bin/benchmark help` got 0 exit code
- ran `/nix/store/bv1hwms0avpnxymgsvwyw9j3n8578k24-etcd-3.3.1-bin/bin/etcd-dump-db -h` got 0 exit code
- ran `/nix/store/bv1hwms0avpnxymgsvwyw9j3n8578k24-etcd-3.3.1-bin/bin/etcd-dump-db --help` got 0 exit code
- ran `/nix/store/bv1hwms0avpnxymgsvwyw9j3n8578k24-etcd-3.3.1-bin/bin/etcd-dump-db help` got 0 exit code
- ran `/nix/store/bv1hwms0avpnxymgsvwyw9j3n8578k24-etcd-3.3.1-bin/bin/etcdctl -h` got 0 exit code
- ran `/nix/store/bv1hwms0avpnxymgsvwyw9j3n8578k24-etcd-3.3.1-bin/bin/etcdctl --help` got 0 exit code
- ran `/nix/store/bv1hwms0avpnxymgsvwyw9j3n8578k24-etcd-3.3.1-bin/bin/etcdctl help` got 0 exit code
- ran `/nix/store/bv1hwms0avpnxymgsvwyw9j3n8578k24-etcd-3.3.1-bin/bin/etcdctl -v` and found version 3.3.1
- ran `/nix/store/bv1hwms0avpnxymgsvwyw9j3n8578k24-etcd-3.3.1-bin/bin/etcdctl --version` and found version 3.3.1
- ran `/nix/store/bv1hwms0avpnxymgsvwyw9j3n8578k24-etcd-3.3.1-bin/bin/etcdctl -h` and found version 3.3.1
- ran `/nix/store/bv1hwms0avpnxymgsvwyw9j3n8578k24-etcd-3.3.1-bin/bin/etcdctl --help` and found version 3.3.1
- ran `/nix/store/bv1hwms0avpnxymgsvwyw9j3n8578k24-etcd-3.3.1-bin/bin/etcdctl help` and found version 3.3.1
- ran `/nix/store/bv1hwms0avpnxymgsvwyw9j3n8578k24-etcd-3.3.1-bin/bin/etcd -h` got 0 exit code
- ran `/nix/store/bv1hwms0avpnxymgsvwyw9j3n8578k24-etcd-3.3.1-bin/bin/etcd --help` got 0 exit code
- ran `/nix/store/bv1hwms0avpnxymgsvwyw9j3n8578k24-etcd-3.3.1-bin/bin/etcd --version` and found version 3.3.1
- found 3.3.1 with grep in /nix/store/bv1hwms0avpnxymgsvwyw9j3n8578k24-etcd-3.3.1-bin
- found 3.3.1 in filename of file in /nix/store/bv1hwms0avpnxymgsvwyw9j3n8578k24-etcd-3.3.1-bin