fix(php-sdk): fix exception spelling

php/src/generate.php

@@ -0,0 +1,29 @@
+<?php
+require_once "vendor/autoload.php";
+
+
+function generate() {
+    return (new FFIMe\FFIMe("libextism.".soext()))
+        ->include("extism.h")
+        ->showWarnings(false)
+        ->codeGen('ExtismLib', __DIR__.'/ExtismLib.php');
+}
+
+function soext() {
+    $platform = php_uname("s");
+    switch ($platform) {
+        case "Darwin":
+            return "dylib";
+        case "Linux": 
+            return "so";
+        case "Windows":
+            return "dll";
+        default:
+            throw new Exception("Extism: unsupported platform ".$platform);
+    }
+}
+
+if (!file_exists(__DIR__."/ExtismLib.php")) {
+    generate();
+}
+