vultr: bump client from 2.7.1 to 2.16.0

[ddymko]

I noticed that GoVultr hasn't been updated in a while so I went ahead and bumped to the latest version 2.16.0. No major changes have been made to DNS so behavior has stayed the same.

Some test output

$  lego [vultr-updates] make build
BIN_OUTPUT: dist/lego
rm -rf dist/ builds/ cover.out
Version: a77d023488dac3abc6bc9cbdf5850d51d88e2f55
go build -trimpath -ldflags '-X "main.version=a77d023488dac3abc6bc9cbdf5850d51d88e2f55"' -o  dist/lego ./cmd/lego/


$  dist [vultr-updates] ./lego -m [email protected] --dns vultr -d '*.dymko.dev' -d 'dymko.dev' --dns-timeout 100 -s https://acme-staging-v02.api.letsencrypt.org/directory  run
2022/05/07 12:07:02 [INFO] [*.dymko.dev, dymko.dev] acme: Obtaining bundled SAN certificate
2022/05/07 12:07:03 [INFO] [*.dymko.dev] AuthURL: https://acme-staging-v02.api.letsencrypt.org/acme/authz-v3/2387104594
2022/05/07 12:07:03 [INFO] [dymko.dev] AuthURL: https://acme-staging-v02.api.letsencrypt.org/acme/authz-v3/2387104604
2022/05/07 12:07:03 [INFO] [*.dymko.dev] acme: use dns-01 solver
2022/05/07 12:07:03 [INFO] [dymko.dev] acme: Could not find solver for: tls-alpn-01
2022/05/07 12:07:03 [INFO] [dymko.dev] acme: Could not find solver for: http-01
2022/05/07 12:07:03 [INFO] [dymko.dev] acme: use dns-01 solver
2022/05/07 12:07:03 [INFO] [*.dymko.dev] acme: Preparing to solve DNS-01
2022/05/07 12:07:03 [INFO] [dymko.dev] acme: Preparing to solve DNS-01
2022/05/07 12:07:03 [INFO] [*.dymko.dev] acme: Trying to solve DNS-01
2022/05/07 12:07:03 [INFO] [*.dymko.dev] acme: Checking DNS record propagation using [8.8.8.8:53]
2022/05/07 12:07:05 [INFO] Wait for propagation [timeout: 1m0s, interval: 2s]
2022/05/07 12:07:05 [INFO] [*.dymko.dev] acme: Waiting for DNS record propagation.
2022/05/07 12:07:20 [INFO] [*.dymko.dev] The server validated our request
2022/05/07 12:07:20 [INFO] [dymko.dev] acme: Trying to solve DNS-01
2022/05/07 12:07:20 [INFO] [dymko.dev] acme: Checking DNS record propagation using [8.8.8.8:53]
2022/05/07 12:07:22 [INFO] Wait for propagation [timeout: 1m0s, interval: 2s]
2022/05/07 12:07:34 [INFO] [dymko.dev] The server validated our request
2022/05/07 12:07:34 [INFO] [*.dymko.dev] acme: Cleaning DNS-01 challenge
2022/05/07 12:07:34 [INFO] [dymko.dev] acme: Cleaning DNS-01 challenge
2022/05/07 12:07:34 [INFO] [*.dymko.dev, dymko.dev] acme: Validations succeeded; requesting certificates
2022/05/07 12:07:34 [INFO] [*.dymko.dev] Server responded with a certificate.

[ldez]

LGTM