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* api-change:``ec2``: Update ec2 client to latest version
* api-change:``transcribe``: Update transcribe client to latest version
* api-change:``mediapackage``: Update mediapackage client to latest version
* api-change:``codepipeline``: Update codepipeline client to latest version
* enhancement:Environment Variables: Ignore env var credentials is values are empty (`1680 <https://github.com/boto/botocore/issues/1680>`__)
* api-change:``rds``: Update rds client to latest version