release: bump version for 1.3.1 release

Author: ddivad195

src/main/kotlin/me/ddivad/judgebot/Main.kt

@@ -58,7 +58,7 @@ suspend fun main(args: Array<String>) {
             field {
                 name = "Build Info"
                 value = "```" +
-                        "Version:   1.3.0\n" +
+                        "Version:   1.3.1\n" +
                         "DiscordKt: ${versions.library}\n" +
                         "Kotlin:    $kotlinVersion" +
                         "```"