Add PEM_write_bio_DHparams binding
diff --git a/src/_cffi_src/openssl/pem.py b/src/_cffi_src/openssl/pem.py
index 846e64e..4eb6bb4 100644
--- a/src/_cffi_src/openssl/pem.py
+++ b/src/_cffi_src/openssl/pem.py
@@ -79,6 +79,7 @@
 int PEM_write_bio_ECPrivateKey(BIO *, EC_KEY *, const EVP_CIPHER *,
                                unsigned char *, int, pem_password_cb *,
                                void *);
+int PEM_write_bio_DHparams(BIO *, DH *);
 """
 
 CUSTOMIZATIONS = """