[fix] changelog extraction path in release workflow

The `awk` step now uses `Simplify.Web/CHANGELOG.md` instead of
`src/Simplify.Web/CHANGELOG.md` because the job inherits the
`working-directory: src` default, making the `src/` prefix redundant.

Author: i4004

.github/workflows/build.yml

@@ -59,7 +59,7 @@ jobs:
       - name: Extract changelog entry
         run: |
           awk '/^## \[/{if(f) exit; f=1; next} f' \
-            src/Simplify.Web/CHANGELOG.md \
+            Simplify.Web/CHANGELOG.md \
             > /tmp/release_notes.md
 
       - name: Create release