Bump dotnet/sdk in /src/WebApi (#18)

Bumps dotnet/sdk from 9.0.303-alpine3.21 to 9.0.304-alpine3.21.

---
updated-dependencies:
- dependency-name: dotnet/sdk
  dependency-version: 9.0.304-alpine3.21
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

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

Author: dependabot[bot]

src/WebApi/Dockerfile

@@ -1,6 +1,6 @@
 # Use Microsoft's official build .NET image
 # https://hub.docker.com/_/microsoft-dotnet-sdk
-FROM mcr.microsoft.com/dotnet/sdk:9.0.303-alpine3.21 AS build
+FROM mcr.microsoft.com/dotnet/sdk:9.0.304-alpine3.21 AS build
 WORKDIR /app
 
 # Copy csproj and restore as distinct layers