Bump protobuf from 3.17.2 to 3.18.3

Bumps [protobuf](https://github.com/protocolbuffers/protobuf) from 3.17.2 to 3.18.3.
- [Release notes](https://github.com/protocolbuffers/protobuf/releases)
- [Changelog](https://github.com/protocolbuffers/protobuf/blob/main/generate_changelog.py)
- [Commits](protocolbuffers/protobuf@v3.17.2...v3.18.3)

---
updated-dependencies:
- dependency-name: protobuf
  dependency-type: direct:production
...

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

Author: dependabot[bot]

setup.py

@@ -37,7 +37,7 @@
         'base58==1.0.0',
         'cffi==1.13.2',
         'cryptography==2.5',
-        'protobuf==3.17.2',
+        'protobuf==3.18.3',
         'prometheus_client==0.7.1',
         'ecdsa==0.13.3',
         'pyyaml==5.3.1',