Added the option to provide the gcloud service account as a string via the environment variable `GCE_SERVICE_ACCOUNT` in addition to the already available option to specify a filepath to a keyfile `GCE_SERVICE_ACCOUNT_FILE`.
- Packages
- Isolate code used by the CLI into the package `cmd`
- (experimental) Add e2e tests for HTTP01, TLS-ALPN-01 and DNS-01, use [Pebble](https://github.com/letsencrypt/pebble) and [challtestsrv](https://github.com/letsencrypt/boulder/tree/master/test/challtestsrv)
- Support non-ascii domain name (punnycode)
- Check all challenges in a predictable order
- No more global exported variables
- Archive revoked certificates
- Fixes revocation for subdomains and non-ascii domains
- Disable pending authorizations
- use pointer for RemoteError/ProblemDetails
- Poll authz URL instead of challenge URL
- The ability for a DNS provider to solve the challenge sequentially
- Check all nameservers in a predictable order
- Option to disable the complete propagation Requirement
- CLI, support for renew with CSR
- CLI, add SAN on renew
- Add command to list certificates.
- Logs every iteration of waiting for the propagation
- update DNSimple client
- update github.com/miekg/dns
