Bump aws-encryption-sdk from 2.0.0 to 2.2.0 in /src (#173)

Bumps [aws-encryption-sdk](https://github.com/aws/aws-encryption-sdk-python) from 2.0.0 to 2.2.0.
- [Release notes](https://github.com/aws/aws-encryption-sdk-python/releases)
- [Changelog](https://github.com/aws/aws-encryption-sdk-python/blob/master/CHANGELOG.rst)
- [Commits](aws/aws-encryption-sdk-python@v2.0.0...v2.2.0)

---
updated-dependencies:
- dependency-name: aws-encryption-sdk
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <[email protected]>

Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Author: dependabot[bot]

src/setup.py

@@ -15,7 +15,7 @@
     python_requires=">=3.6",
     install_requires=[
         "boto3>=1.10.20",
-        "aws-encryption-sdk==2.0.0",
+        "aws-encryption-sdk==2.2.0",
         'dataclasses;python_version<"3.7"',
     ],
     license="Apache License 2.0",