Use Net_SMTP-1.7.x and Net_Sieve-1.5.x (Roundcube fork), update changelog (#1490416)

CHANGELOG

@@ -1,6 +1,7 @@
 CHANGELOG Roundcube Webmail
 ===========================
 
+- PHP7 compatibility fixes (#1490416)
 - Security: Improve randomness of security tokens (#1490529)
 - Security: Use random security tokens instead of hashes based on encryption key (#1490404)
 - Security: Improved encrypt/decrypt methods with option to choose the cipher_method (#1489719)

composer.json-dist

@@ -11,6 +11,10 @@
             "type": "composer",
             "url": "https://plugins.roundcube.net/"
         },
+        {
+            "type": "vcs",
+            "url": "https://github.com/roundcube/Net_Sieve.git"
+        },
         {
             "type": "vcs",
             "url": "https://git.kolab.org/diffusion/PNL/php-net_ldap.git"
@@ -21,10 +25,10 @@
         "roundcube/plugin-installer": "~0.1.6",
         "pear-pear.php.net/auth_sasl": "~1.0.6",
         "pear-pear.php.net/net_idna2": "~0.1.1",
-        "pear-pear.php.net/net_sieve": "~1.3.4",
         "pear-pear.php.net/mail_mime": "~1.9.0",
-        "pear-pear.php.net/net_smtp": "~1.6.3",
+        "pear-pear.php.net/net_smtp": "~1.7.1",
-        "pear-pear.php.net/crypt_gpg": "*"
+        "pear-pear.php.net/crypt_gpg": "*",
+        "roundcube/net_sieve": "~1.5.0"
     },
     "require-dev": {
         "phpunit/phpunit": "*"