Bump DiscordRPC plugin to v13 (#715)

Co-authored-by: cat_or_not <41955154+catornot@users.noreply.github.com>

Author: GeckoEidechse

.github/workflows/release.yml

@@ -34,7 +34,7 @@ jobs:
           wget "https://github.com/R2Northstar/NorthstarLauncher/releases/download/${{ env.NORTHSTAR_VERSION }}/northstar-launcher.zip"
       - name: Download DiscordRPC plugin
         run:
-          wget "https://github.com/R2Northstar/NorthstarDiscordRPC/releases/download/v12/northstar-discord-rpc.zip"
+          wget "https://github.com/R2Northstar/NorthstarDiscordRPC/releases/download/v13/northstar-discord-rpc.zip"
       - name: Download compiled stubs
         run:
           wget "https://github.com/R2Northstar/NorthstarStubs/releases/download/v1/NorthstarStubs.zip"