Upgrade notes for SimpleSAMLphp 1.13

• The RSA_1.5 (RSA with PKCS#1 v1.5 padding) algorithm is now longer allowed by default. This means messages received that use this algorithm will fail to decrypt.
• Several functions, classes and interfaces are now deprecated. Please check your code if you are using the API.
• A workaround related to performance issues when processing large metadata sets was included in 1.13.2. This workaround is experimental and could have unexpected side effects.