Use Base64.strict_encode64 instead of Base64.encode64

Attachments must be base64 encoded, using `Base64.strict_encode64` where no
line feeds are added.

lib/sendgrid/helpers/mail/attachment.rb

@@ -49,7 +49,7 @@ def encode(io)
       # in binary mode, but at least we can faithfully convey the
       # bytes.
       str = str.encode('UTF-8') unless io.respond_to?(:binmode?) && io.binmode?
-      Base64.encode64 str
+      Base64.strict_encode64 str
     end
   end
 end

mail_helper_v3.md

@@ -307,7 +307,7 @@ plain_text_content = 'and easy to do anywhere, even with Ruby'
 html_content = '<strong>and easy to do anywhere, even with Ruby</strong>'
 msg = SendGrid::Message.new(from, to, subject, plain_text_content, html_content)
 bytes = File.read('/path/to/the/attachment.pdf')
-encoded = Base64.encode64(bytes)
+encoded = Base64.strict_encode64(bytes)
 msg.add_attachment('balance_001.pdf',
                    encoded,
                    'application/pdf',

test/sendgrid/helpers/mail/test_attachment.rb

@@ -18,13 +18,13 @@ def test_io_enocding
     attachment.content = StringIO.new(SAMPLE_INPUT)
 
     expected = {
-      "content" => "RXMgYmzDvGh0IHNvIGdyw7xuIHdpZSBCbMO8dGVuIGJsw7xoJ24gaW0gRnLD\nvGhsaW5nCkVzIGJsw7xodCBzbyBncsO8biB3aWUgQmzDvHRlbiBibMO8aCdu\nIGltIEZyw7xobGluZwpFcyBibMO8aHQgc28gZ3LDvG4gd2llIEJsw7x0ZW4g\nYmzDvGgnbiBpbSBGcsO8aGxpbmcKRXMgYmzDvGh0IHNvIGdyw7xuIHdpZSBC\nbMO8dGVuIGJsw7xoJ24gaW0gRnLDvGhsaW5nCkVzIGJsw7xodCBzbyBncsO8\nbiB3aWUgQmzDvHRlbiBibMO8aCduIGltIEZyw7xobGluZwo=\n"
+      "content" => "RXMgYmzDvGh0IHNvIGdyw7xuIHdpZSBCbMO8dGVuIGJsw7xoJ24gaW0gRnLDvGhsaW5nCkVzIGJsw7xodCBzbyBncsO8biB3aWUgQmzDvHRlbiBibMO8aCduIGltIEZyw7xobGluZwpFcyBibMO8aHQgc28gZ3LDvG4gd2llIEJsw7x0ZW4gYmzDvGgnbiBpbSBGcsO8aGxpbmcKRXMgYmzDvGh0IHNvIGdyw7xuIHdpZSBCbMO8dGVuIGJsw7xoJ24gaW0gRnLDvGhsaW5nCkVzIGJsw7xodCBzbyBncsO8biB3aWUgQmzDvHRlbiBibMO8aCduIGltIEZyw7xobGluZwo="
     }
 
     json = attachment.to_json
 
     # Double check that the decoded json matches original input.
-    decoded = Base64.decode64(json["content"]).force_encoding('UTF-8').encode
+    decoded = Base64.strict_decode64(json["content"]).force_encoding('UTF-8').encode
 
     assert_equal(decoded, SAMPLE_INPUT)