docs: tweak readme filename casing

README.md

@@ -120,7 +120,7 @@ To provide a signing identify for macOS build, use `BOUNDARY_DESKTOP_SIGNING_IDE
 environment variable to set signing certificate name (e.g Developer ID Application: * (*)).
 
 Assets are saved to `ui/desktop/electron-app/out/make/`.
-DMG packaged desktop UI is available at asset location as `Boundary.dmg`.
+DMG packaged desktop UI is available at asset location as `boundary.dmg`.
 
 ### Committing