added template for query parameters

lib/codegen/php/curl.dart

@@ -15,6 +15,17 @@ class PHPcURLCodeGen {
   final String kTemplateUri = """
 \$uri = "{{uri}}";
 
+""";
+
+  //defining query parameters
+  String kTemplateParams = """
+
+\$queryParams = [{{params}}];
+\$queryString = "?" . http_build_query(\$queryParams);
+if (count(\$queryParams) > 0) {
+    \$uri .= \$queryString;
+}
+
 """;
 
   //initialising the request