build: rename atom.ico to electron.ico (#23099)

BUILD.gn

@@ -1078,7 +1078,7 @@ if (is_mac) {
       # See https://github.com/nodejs/node-gyp/commit/52ceec3a6d15de3a8f385f43dbe5ecf5456ad07a
       ldflags += [ "/DEF:" + rebase_path("build/electron.def", root_build_dir) ]
       inputs = [
-        "shell/browser/resources/win/atom.ico",
+        "shell/browser/resources/win/electron.ico",
         "build/electron.def",
       ]
     }

shell/browser/resources/win/electron.rc

@@ -103,5 +103,5 @@ END
 // Icon
 //
 
-IDR_MAINFRAME           ICON                    "atom.ico"
+IDR_MAINFRAME           ICON                    "electron.ico"
 /////////////////////////////////////////////////////////////////////////////