chore: add 1.21.5 to modrinth gameVersions

Author: Kaseax

sign-paper/build.gradle.kts

@@ -42,9 +42,10 @@ modrinth {
         "1.21.1",
         "1.21.2",
         "1.21.3",
-        "1.21.4"
+        "1.21.4",
+	"1.21.5"
     )
     loaders.add("paper")
     changelog.set("https://docs.simplecloud.app/changelog")
     syncBodyFrom.set(rootProject.file("README.md").readText())
-}
+}