Bump protobuf from 3.17.3 to 3.18.3 in /WebApp

Bumps [protobuf](https://github.com/protocolbuffers/protobuf) from 3.17.3 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@v3.17.3...v3.18.3)

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

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

Author: dependabot[bot]

WebApp/requirements.txt

@@ -24,7 +24,7 @@ numpy==1.19.5
 oauthlib==3.2.2
 opt-einsum==3.3.0
 pandas==1.3.0
-protobuf==3.17.3
+protobuf==3.18.3
 pyasn1==0.4.8
 pyasn1-modules==0.2.8
 python-dateutil==2.8.2