Correct casing for DS_Store in .gitignore (#6787)

.gitignore

@@ -25,7 +25,7 @@ quantum/version.h
 CMakeLists.txt
 cmake-build-debug
 doxygen/
-.DS_STORE
+.DS_Store
 /util/wsl_downloaded
 /util/win_downloaded
 /keyboards/*/Makefile