Add game compatibility: Metal Slug (#44)

Author: mrcaique

docs/wiki/Game-Compatibility.md

@@ -65,6 +65,7 @@ While GOG does not officially support GOG Galaxy features (achievements and lead
 |[Horizon Zero Dawn Complete Edition](https://gog.com/game/horizon_zero_dawn_complete_edition)|7517962 (1/18/2022)|🔲 Not Available|[commit `c4715bf`](https://github.com/imLinguin/comet/commit/c4715bfa186f9b8955b842d57fd6f17fc5209f26)|🔲 No|🟩 Achievements 🔲 Leaderboard| Achievements do work.|
 |[Indivisible](https://www.gog.com/game/indivisible)|42940 (6/22/2020)|🟩 Yes|[version 0.1.0](https://github.com/imLinguin/comet/releases/tag/v0.1.0)|🔲 No|🟩 Achievements 🔲 Leaderboard|Achievements do work.|
 |[Kingdom Come: Deliverance](https://www.gog.com/game/kingdom_come_deliverance)|1.9.6-404-504czi3 |🔲 Not available|[version `0.1.2`](https://github.com/imLinguin/comet/releases/tag/v0.1.2)|🟩 Yes|🟩 Achievements 🔲 Leaderboard||
+|[Metal Slug](https://www.gog.com/en/game/metal_slug)|Version gog-3 - 26/05/2017|🔲 Not Available|[version `v0.1.2`](https://github.com/imLinguin/comet/releases/tag/v0.1.2)|🔲 No|🟩 Achievements 🟩 Leaderboard|Achievements and leaderboard do work as of `v0.1.2`. Multiplayer not tested yet.|
 |[Quake II](https://www.gog.com/game/quake_ii_quad_damage)|5984 (11/01/2023)|🔲 Not available|[version `0.1.1`](https://github.com/imLinguin/comet/releases/tag/v0.1.1)|🔲 No|🟩 Achievements 🔲 Leaderboard|Achievements work as expected. The game needs OpenID support introduced in comet v0.1.1|
 |[STONKS-9800: Stock Market Simulator](https://www.gog.com/game/stonks9800_stock_market_simulator)|0.4.2.5 (04/04/2024)|🔲 Not Available|[commit `55e4025`](https://github.com/imLinguin/comet/commit/55e402538df3bff354bf2e1e9a54fa4e5e091122)|❓ Unknown|❌ Achievements 🔲 Leaderboard|Game specific issue related to the GOG SDK library used. See [#26](https://github.com/imLinguin/comet/issues/26#issuecomment-2053667485) for any information and updates. Game did not connect to GOG via Comet with and without the dummy Service.|
 |[Stardew Valley](https://www.gog.com/game/stardew_valley)|1.6.5.24110.6670590629 (4/19/2024)|🟩 Yes|[commit `c4715bf`](https://github.com/imLinguin/comet/commit/c4715bfa186f9b8955b842d57fd6f17fc5209f26)|🔲 No|🔲 Achievements 🔲 Leaderboard|The game uses Galaxy SDK for multiplayer only.|