Update base64.h to set base64 linesize to 20000

We cannot have line endings in our signed xml and thus need the line size to be artificially high to prevent this.

include/xmlsec/base64.h

@@ -26,7 +26,7 @@ extern "C" {
  *
  * The default maximum base64 encoded line size.
  */
-#define XMLSEC_BASE64_LINESIZE                          64
+#define XMLSEC_BASE64_LINESIZE                          20000
 
 XMLSEC_EXPORT int               xmlSecBase64GetDefaultLineSize  (void);
 XMLSEC_EXPORT void              xmlSecBase64SetDefaultLineSize  (int columns);