Bump amqp-client from 3.5.3 to 5.5.1 in /core (#1076)

Bumps [amqp-client](https://github.com/rabbitmq/rabbitmq-java-client) from 3.5.3 to 5.5.1.
<details>
<summary>Release notes</summary>

*Sourced from [amqp-client's releases](https://github.com/rabbitmq/rabbitmq-java-client/releases).*

> ## 5.5.1
> This is a patch release with a bug fix. All users of the 5.x.x series are encouraged to upgrade to this version.
> 
> # Changes between 5.5.0 and 5.5.1
> 
> ## Record recoverable entities in RPC channel methods
> 
> GitHub issue: [#425](https://github-redirect.dependabot.com/rabbitmq/rabbitmq-java-client/issues/425) 
> 
> ## 5.5.0
> This is a maintenance release with 2 new features and a bug fix. All users of the 5.x.x series are encouraged to upgrade to this version.
> 
> # Changes between 5.4.3 and 5.5.0
> 
> ## Add traffic listener
> 
> GitHub issue: [#411](https://github-redirect.dependabot.com/rabbitmq/rabbitmq-java-client/issues/411)
> 
> ## Connection recovery runs into timeouts when using NIO
> 
> GitHub issue: [#413](https://github-redirect.dependabot.com/rabbitmq/rabbitmq-java-client/issues/413)
> 
> ## Provide factories to create NIO artefacts
> 
> GitHub issue: [#410](https://github-redirect.dependabot.com/rabbitmq/rabbitmq-java-client/issues/410)
> 
> ## 4.9.0
> This is a maintenance release with 2 new features and a bug fix. All users of the 4.x.x and 3.6.x series are encouraged to upgrade to this version.
> 
> # Changes between 4.8.3 and 4.9.0
> 
> ## Add traffic listener
> 
> GitHub issue: [#411](https://github-redirect.dependabot.com/rabbitmq/rabbitmq-java-client/issues/411)
> 
> ## Connection recovery runs into timeouts when using NIO
> 
> GitHub issue: [#413](https://github-redirect.dependabot.com/rabbitmq/rabbitmq-java-client/issues/413)
> 
> ## Provide factories to create NIO artefacts
> 
> GitHub issue: [#410](https://github-redirect.dependabot.com/rabbitmq/rabbitmq-java-client/issues/410)
> 
> ## 5.5.0.RC1
> This is a pre-release for 5.5.0, a maintenance release with 2 new features and a bug fix. All users of the 5.x.x series are encouraged to test this version.
> 
> # Changes between 5.4.0 and 5.5.0.RC1
> 
> ## Add traffic listener
> 
></table> ... (truncated)
</details>
<details>
<summary>Changelog</summary>

*Sourced from [amqp-client's changelog](https://github.com/rabbitmq/rabbitmq-java-client/blob/v5.5.1/release-versions.txt).*

> RELEASE_VERSION="5.5.1"
> DEVELOPMENT_VERSION="5.5.2-SNAPSHOT"
</details>
<details>
<summary>Commits</summary>

- See full diff in [compare view](https://github.com/rabbitmq/rabbitmq-java-client/commits/v5.5.1)
</details>
<br />

[![Dependabot compatibility score](https://api.dependabot.com/badges/compatibility_score?dependency-name=com.rabbitmq:amqp-client&package-manager=gradle&previous-version=3.5.3&new-version=5.5.1)](https://dependabot.com/compatibility-score.html?dependency-name=com.rabbitmq:amqp-client&package-manager=gradle&previous-version=3.5.3&new-version=5.5.1)

Dependabot will resolve any conflicts with this PR as long as you don't alter it yourself. You can also trigger a rebase manually by commenting `@dependabot rebase`.

[//]: # (dependabot-automerge-start)
[//]: # (dependabot-automerge-end)

---

**Note:** This repo was added to Dependabot recently, so you'll receive a maximum of 5 PRs for your first few update runs. Once an update run creates fewer than 5 PRs we'll remove that limit.

You can always request more updates by clicking `Bump now` in your [Dependabot dashboard](https://app.dependabot.com).

<details>
<summary>Dependabot commands and options</summary>
<br />

You can trigger Dependabot actions by commenting on this PR:
- `@dependabot rebase` will rebase this PR
- `@dependabot recreate` will recreate this PR, overwriting any edits that have been made to it
- `@dependabot merge` will merge this PR after your CI passes on it
- `@dependabot cancel merge` will cancel a previously requested merge
- `@dependabot reopen` will reopen this PR if it is closed
- `@dependabot badge me` will comment on this PR with code to add a "Dependabot enabled" badge to your readme

Additionally, you can set the following in the `.dependabot/config.yml` file in this repo:
- Update frequency (including time of day and day of week)
- Automerge options (never/patch/minor, and dev/runtime dependencies)
- Pull request limits (per update run and/or open at any time)
- Out-of-range updates (receive only lockfile updates, if desired)
- Security updates (receive only security updates, if desired)

Finally, you can contact us by mentioning @dependabot.

</details>

core/build.gradle

@@ -117,7 +117,7 @@ dependencies {
     }
 
     testCompile 'redis.clients:jedis:3.0.0'
-    testCompile 'com.rabbitmq:amqp-client:3.5.3'
+    testCompile 'com.rabbitmq:amqp-client:5.5.1'
     testCompile 'org.mongodb:mongo-java-driver:3.0.2'
     testCompile ('org.mockito:mockito-core:1.10.19') {
         exclude(module: 'hamcrest-core')