🔒 Add kwargs to deprecated +LOGIN+ and +CRAM-MD5+

These are added to give _all_ mechanisms the same basic argument
semantics.  If it were just for `Net::IMAP`, I'd say it's not worth it.
However, to make this `SASL` implementation fully compatible with
others—such as `net-smtp`.

lib/net/imap/sasl/cram_md5_authenticator.rb

@@ -14,13 +14,17 @@
 # of cleartext and recommends TLS version 1.2 or greater be used for all
 # traffic.  With TLS +CRAM-MD5+ is okay, but so is +PLAIN+
 class Net::IMAP::SASL::CramMD5Authenticator
-  def initialize(user, password, warn_deprecation: true, **_ignored)
+  def initialize(user = nil, pass = nil,
+                 authcid: nil, username: nil,
+                 password: nil,
+                 warn_deprecation: true,
+                 **)
     if warn_deprecation
       warn "WARNING: CRAM-MD5 mechanism is deprecated." # TODO: recommend SCRAM
     end
     require "digest/md5"
-    @user = user
-    @password = password
+    @user = authcid || username || user
+    @password = password || pass
     @done = false
   end
 

lib/net/imap/sasl/login_authenticator.rb

@@ -23,12 +23,16 @@ class Net::IMAP::SASL::LoginAuthenticator
   STATE_DONE = :DONE
   private_constant :STATE_USER, :STATE_PASSWORD, :STATE_DONE
 
-  def initialize(user, password, warn_deprecation: true, **_ignored)
+  def initialize(user = nil, pass = nil,
+                 authcid: nil, username: nil,
+                 password: nil,
+                 warn_deprecation: true,
+                 **)
     if warn_deprecation
       warn "WARNING: LOGIN SASL mechanism is deprecated. Use PLAIN instead."
     end
-    @user = user
-    @password = password
+    @user = authcid || username || user
+    @password = password || pass
     @state = STATE_USER
   end