fix: memory leak in clib_package_new (#323)

Direct leak of 32 byte(s) in 1 object(s) allocated from:
    0 malloc
    1 json_object_init clib/deps/parson/parson.c:291:42
    2 json_value_init_object clib/deps/parson/parson.c:1077:31
    3 parse_object_value clib/deps/parson/parson.c:580:32
    4 parse_value clib/deps/parson/parson.c:561:20
    5 parse_object_value clib/deps/parson/parson.c:600:21
    6 parse_value clib/deps/parson/parson.c:561:20
    7 json_parse_string clib/deps/parson/parson.c:910:12
    8 clib_package_new clib/src/common/clib-package.c:468:16
    9 clib_package_load_from_manifest clib/src/common/clib-package.c:259:9

src/common/clib-package.c

@@ -513,6 +513,8 @@ clib_package_t *clib_package_new(const char *json, int verbose) {
       for (unsigned int i = 0; i < json_array_get_count(flags); i++) {
         char *flag = json_array_get_string_safe(flags, i);
         if (flag) {
+          char *old_flags = pkg->flags;
+
           if (!pkg->flags) {
             pkg->flags = "";
           }
@@ -521,6 +523,7 @@ clib_package_t *clib_package_new(const char *json, int verbose) {
             goto cleanup;
           }
 
+          free(old_flags);
           free(flag);
         }
       }