Update boto3 to 1.9.6 (#1157)

This PR updates [boto3](https://pypi.org/project/boto3) from **1.9.1** to **1.9.6**.



<details>
  <summary>Changelog</summary>
  
  
   ### 1.9.6
   ```
   =====

* bugfix:Serialization: [``botocore``] Fixes `1557 &lt;https://github.com/boto/botocore/issues/1557&gt;`__. Fixed a regression in serialization where request bodies would be improperly encoded.
* api-change:``es``: [``botocore``] Update es client to latest version
* api-change:``rekognition``: [``botocore``] Update rekognition client to latest version
   ```
   
  
  
   ### 1.9.5
   ```
   =====

* api-change:``codebuild``: [``botocore``] Update codebuild client to latest version
* api-change:``elastictranscoder``: [``botocore``] Update elastictranscoder client to latest version
* api-change:``ecs``: [``botocore``] Update ecs client to latest version
* api-change:``ec2``: [``botocore``] Update ec2 client to latest version
* api-change:``cloudwatch``: [``botocore``] Update cloudwatch client to latest version
* api-change:``secretsmanager``: [``botocore``] Update secretsmanager client to latest version
* api-change:``elasticache``: [``botocore``] Update elasticache client to latest version
   ```
   
  
  
   ### 1.9.4
   ```
   =====

* enhancement:s3: [``botocore``] Adds encoding and decoding handlers for ListObjectsV2 `1552 &lt;https://github.com/boto/botocore/issues/1552&gt;`__
* api-change:``polly``: [``botocore``] Update polly client to latest version
   ```
   
  
  
   ### 1.9.3
   ```
   =====

* api-change:``ses``: [``botocore``] Update ses client to latest version
* api-change:``ec2``: [``botocore``] Update ec2 client to latest version
* api-change:``fms``: [``botocore``] Update fms client to latest version
* api-change:``connect``: [``botocore``] Update connect client to latest version
   ```
   
  
  
   ### 1.9.2
   ```
   =====

* api-change:``opsworkscm``: [``botocore``] Update opsworkscm client to latest version
* api-change:``ssm``: [``botocore``] Update ssm client to latest version
   ```
   
  
</details>


 

<details>
  <summary>Links</summary>
  
  - PyPI: https://pypi.org/project/boto3
  - Changelog: https://pyup.io/changelogs/boto3/
  - Repo: https://github.com/boto/boto3
</details>

requirements.txt

@@ -51,9 +51,9 @@ newrelic==4.4.0.103 \
 requests==2.19.1 \
     --hash=sha256:63b52e3c866428a224f97cab011de738c36aec0185aa91cfacd418b5d58911d1 \
     --hash=sha256:ec22d826a36ed72a7358ff3fe56cbd4ba69dd7a6718ffd450ff0e9df7a47ce6a
-boto3==1.9.1 \
-    --hash=sha256:0115b91312737ee24b263c45573a7ab7def6e7fa22e4cd3814ef477ae811f6cd \
-    --hash=sha256:d0f77b445f16e3767d8d9f7377e4bdbdfe39de12265ca4802d6dc1179409f91c
+boto3==1.9.6 \
+    --hash=sha256:7f882ebeede19ede13477fde7f8919105876ec42d68c0def23b69802b1ea9f0a \
+    --hash=sha256:9764a5d7ca8a896b6166b589497a8e71573f964732ebdba4afccfe336e1ae68d
 botocore==1.12.7 \
     --hash=sha256:22c1460e0ff40a4d25198b8d807a24fc7ecd95162d72d3e1496a7a571ae7468d \
     --hash=sha256:5fca20d37627823d50a101ad9acb5a0b1f6d7f82b6d84cb7a33afe8d68a03f75