Bump boto3 from 1.26.78 to 1.26.84 in /stix_shifter

Bumps [boto3](https://github.com/boto/boto3) from 1.26.78 to 1.26.84.
- [Release notes](https://github.com/boto/boto3/releases)
- [Changelog](https://github.com/boto/boto3/blob/develop/CHANGELOG.rst)
- [Commits](boto/boto3@1.26.78...1.26.84)

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

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

stix_shifter/requirements.txt

@@ -1,6 +1,6 @@
 adal==1.2.7
 antlr4-python3-runtime==4.8
-boto3==1.26.78
+boto3==1.26.84
 flask==2.2.3
 pyOpenSSL==23.0.0
 flatten_json==0.1.13