Add change note

Author: tamasvajk

csharp/ql/lib/change-notes/2024-01-31-compilation-expanded-args.md

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+---
+category: minorAnalysis
+---
+* Added a new database relation to store compiler arguments specified inside `@[...].rsp` file arguments. The arguments
+are returned by `Compilation::getExpandedArgument/1` and `Compilation::getExpandedArguments/0`.