[BestPractice] Change this constant to a 'static' read-only property.

[github-actions]

Codacy ID: 2259b7e6b226ce55f522b01f50c29a41

File: FileProcessor/Endpoints/FileEndpoints.cs
Line: 10
Rule: BestPractice (Warning)
Commit: null

Code Snippet:

    public const string BaseRoute = "api/files";