Added _ENABLE_MD5_SIGNATURES into features list

Specifically, 'POLARSSL_SSL_ENABLE_MD5_SIGNATURES' into version_features.c
diff --git a/library/version_features.c b/library/version_features.c
index b8b3a4a..d5f4468 100644
--- a/library/version_features.c
+++ b/library/version_features.c
@@ -345,6 +345,9 @@
 #if defined(POLARSSL_SSL_TRUNCATED_HMAC)
     "POLARSSL_SSL_TRUNCATED_HMAC",
 #endif /* POLARSSL_SSL_TRUNCATED_HMAC */
+#if defined(POLARSSL_SSL_ENABLE_MD5_SIGNATURES)
+    "POLARSSL_SSL_ENABLE_MD5_SIGNATURES",
+#endif /* POLARSSL_SSL_ENABLE_MD5_SIGNATURES */
 #if defined(POLARSSL_SSL_SET_CURVES)
     "POLARSSL_SSL_SET_CURVES",
 #endif /* POLARSSL_SSL_SET_CURVES */