Bump boto3 from 1.20.49 to 1.21.3 in /{{cookiecutter.project_slug}} (#334)

Bumps [boto3](https://github.com/boto/boto3) from 1.20.49 to 1.21.3.
- [Release notes](https://github.com/boto/boto3/releases)
- [Changelog](https://github.com/boto/boto3/blob/develop/CHANGELOG.rst)
- [Commits](boto/boto3@1.20.49...1.21.3)

---
updated-dependencies:
- dependency-name: boto3
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>

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

Author: dependabot[bot]

{{cookiecutter.project_slug}}/Pipfile

@@ -11,7 +11,7 @@ python_version = "3.8"
 [packages]
 cryptography = "~=36.0.1"
 django = "~=2.2.26"
-"boto3" = "~=1.20.49"
+"boto3" = "~=1.21.3"
 django-environ = "~=0.8.1"
 django-storages = "~=1.12"
 psycopg2 = "<2.9"