[maven-release-plugin] copy for tag 1.30.3

Fixes typo

[maven-release-plugin] copy for tag 1.30.2

Lack of timestamp in server-only spans implies shared (openzipkin#1690)

When "sr" is present without a timestamp, we assume this is a shared
span. Moving this signal to the converter allows stackdriver-zipkin to
reuse this when converting to their single-host types.

See openzipkin/openzipkin.github.io#49

[maven-release-plugin] copy for tag 1.30.1

[maven-release-plugin] copy for tag 1.30.0

[maven-release-plugin] copy for tag 1.29.4

Adds SpanDecoder.DETECTING_DECODER (openzipkin#1688)

A couple things were found integrating zipkin2 json format with existing
collectors.
 * Only Kafka has a legacy encoding of single span per message
   * We shouldn't assume this encoding is supported for others
 * Azure Event Hubs decodes messages decoupled from collection
   * We need to move the detecting decode logic to avoid copy/pasting it

Accepts Zipkin v2 Span format in all current transports (openzipkin#1684

)

This accepts the json format from openzipkin#1499 on current transports. It does
so by generalizing format detection from the two Kafka libraries, and
a new `SpanDecoder` interface. Types are still internal, but this allows
us to proceed with other work in openzipkin#1644, including implementing reporters
in any language.

Concretely, you can send a json list of span2 format as a Kafka or Http
message. If using http, use the /api/v2/spans endpoint like so:

```bash
$ curl -X POST -s localhost:9411/api/v2/spans -H'Content-Type: application/json' -d'[{
  "timestamp_millis": 1502101460678,
  "traceId": "9032b04972e475c5",
  "id": "9032b04972e475c5",
  "kind": "SERVER",
  "name": "get",
  "timestamp": 1502101460678880,
  "duration": 612898,
  "localEndpoint": {
    "serviceName": "brave-webmvc-example",
    "ipv4": "192.168.1.113"
  },
  "remoteEndpoint": {
    "serviceName": "",
    "ipv4": "127.0.0.1",
    "port": 60149
  },
  "tags": {
    "error": "500 Internal Server Error",
    "http.path": "/a"
  }
}]'
```

Version updates, notably spring boot and AWS sdk (openzipkin#1687)