fix: Update icon path in Windows resource file for rpi-imager

- Changed the icon path in rpi-imager.rc.in from "../icons/rpi-imager.ico" to "../src/icons/rpi-imager.ico" to reflect the new directory structure.

Author: tdewey-rpi

src/windows/rpi-imager.rc.in

@@ -1,6 +1,6 @@
 #include <windows.h>
 
-IDI_ICON1 ICON DISCARDABLE "../icons/rpi-imager.ico"
+IDI_ICON1 ICON DISCARDABLE "../src/icons/rpi-imager.ico"
 CREATEPROCESS_MANIFEST_RESOURCE_ID RT_MANIFEST "rpi-imager.manifest"
 
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