0.15.7

• [fix] handle CRL with optional nextUpdate absent
• [compat] handle nil dates in Certificate#sign
• [fix] null guard for public key in PKey#toJava
• [fix] missing null guard in SSLSocket#alpn_protocol
• [fix] missing throw in PKey::EC::Point#add
• [fix] DH#params returned pub_key and priv_key swapped
• [fix] compat with JRuby < 9.2.10 after API change (#348)
• [fix] Cipher#reset when key not set (jruby/jruby#5776)
• [fix] encode Netscape IA5String extensions correctly (#349)
• [fix] Store#add_file raises when no certificate or CRL (#285)
• [fix] PSS auto salt-length verify failed due leading zeros