Bump alpine from 3.22 to 3.23 in /services/mcp-firewall (#23)

Bumps alpine from 3.22 to 3.23.

---
updated-dependencies:
- dependency-name: alpine
  dependency-version: '3.23'
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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

Author: dependabot[bot]

services/mcp-firewall/Dockerfile

@@ -5,7 +5,7 @@ RUN go mod download
 COPY . .
 RUN CGO_ENABLED=0 go build -o /mcp-firewall .
 
-FROM alpine:3.22@sha256:310c62b5e7ca5b08167e4384c68db0fd2905dd9c7493756d356e893909057601
+FROM alpine:3.23@sha256:5b10f432ef3da1b8d4c7eb6c487f2f5a8f096bc91145e68878dd4a5019afde11
 RUN apk add --no-cache ca-certificates
 COPY --from=build /mcp-firewall /usr/local/bin/mcp-firewall
 USER 65534:65534