Bump stix2-patterns from 1.3.2 to 2.0.0 in /stix_shifter

Bumps [stix2-patterns](https://github.com/oasis-open/cti-pattern-validator) from 1.3.2 to 2.0.0.
- [Release notes](https://github.com/oasis-open/cti-pattern-validator/releases)
- [Changelog](https://github.com/oasis-open/cti-pattern-validator/blob/master/CHANGELOG.rst)
- [Commits](oasis-open/cti-pattern-validator@v1.3.2...v2.0.0)

---
updated-dependencies:
- dependency-name: stix2-patterns
  dependency-type: direct:production
  update-type: version-update:semver-major
...

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

Author: dependabot[bot]

stix_shifter/requirements.txt

@@ -6,7 +6,7 @@ pyOpenSSL==21.0.0
 flatten_json==0.1.13
 python-dateutil==2.8.2
 requests_toolbelt==0.9.1
-stix2-patterns==1.3.2
+stix2-patterns==2.0.0
 stix2-validator==3.0.2
 xmltodict==0.13.0
 jsonmerge==1.8.0