package/sdl2_image: add SDL2_IMAGE_CPE_ID_PRODUCT

package/sdl2_image: add SDL2_IMAGE_CPE_ID_PRODUCT

cpe:2.3:a:libsdl:sdl_image is a valid CPE identifier for this package:

  https://nvd.nist.gov/products/cpe/search/results?namingFormat=2.3&keyword=cpe%3A2.3%3Aa%3Alibsdl%3Asdl2_image

Indeed, cpe:2.3:a:libsdl:sdl2_image contains a single CPE entry for
version 2.0.4, all the other entries have been deprecated in favor of
cpe:2.3:a:libsdl:sdl_image:

  <cpe-item name="cpe:/a:libsdl:sdl2_image:2.0.3" deprecated="true" deprecation_date="2020-07-28T15:42:37.767Z">
      <reference href="https://www.libsdl.org/projects/SDL_image/">Product</reference>
    <cpe-23:cpe23-item name="cpe:2.3:a:libsdl:sdl2_image:2.0.3:*:*:*:*:*:*:*">
        <cpe-23:deprecated-by name="cpe:2.3:a:libsdl:sdl_image:2.0.3:*:*:*:*:*:*:*" type="NAME_CORRECTION"/>
  <cpe-item name="cpe:/a:libsdl:sdl2_image:2.0.4">
      <reference href="http://hg.libsdl.org/SDL_image/">Version</reference>
    <cpe-23:cpe23-item name="cpe:2.3:a:libsdl:sdl2_image:2.0.4:*:*:*:*:*:*:*"/>
  <cpe-item name="cpe:/a:libsdl:sdl2_image:2.0.5" deprecated="true" deprecation_date="2020-07-28T15:42:40.500Z">
      <reference href="http://hg.libsdl.org/SDL_image/">Version</reference>
    <cpe-23:cpe23-item name="cpe:2.3:a:libsdl:sdl2_image:2.0.5:*:*:*:*:*:*:*">
        <cpe-23:deprecated-by name="cpe:2.3:a:libsdl:sdl_image:2.0.5:*:*:*:*:*:*:*" type="NAME_CORRECTION"/>:

Signed-off-by: Fabrice Fontaine <fontaine.fabrice@gmail.com>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>