Update README.md

Merge pull request #41 from olleolleolle/patch-1

Refer to https:// in mail_interceptor.gemspec

Merge pull request #40 from johnpaulashenfelter/correct-engine-filename

Fix type in engine.rb filename

Updated dependencies (#39)

Merge pull request #35 from bigbinary/fix-zerobounce-for-privaterelay-apple-id

Skipped zerobounce verification for privaterelay apple id

Merge pull request #34 from bigbinary/set-default-value-of-bcc-to-false

correct test cases

Set default value of options :ignore_bcc, and :ignore_cc to false

Merge pull request #33 from bigbinary/integrated-zerobounce

Removed key and improved zerobounce_enabled check

Zerobounce integrated

Merge pull request #32 from bigbinary/add-loose-versioning