v0.4.0: Custom dial contexts and OAUTH2 support

[wneessen]

This release adds two great improvements to go-mail.

Custom dial contexts

The newly added option allows for providing custom dial contexts, to use i. e. for some more extra processes in establish a connection such as using proxy, DNS hook, and so on. The dial context can be provided via the WithDialContextFunc option on the Client. Huge thanks to @sters for their contribution to the project!

OAUTH2 support

@drakkan (Developer of the excellent SFTPGO) added a new SMTP auth option for OAUTH2 authentication tokens (aka XOAUTH2). We now support Google and Microsoft O365 OAUTH2 authentication tokens. With this, go-mail now support 4 different SMTP Auth variants: LOGIN, PLAIN, CRAM-MD, XOAUTH2.
Thanks again @drakkan for this contribution and also big thanks to @james-d-elliott for helping to test this new option and providing their broad knowledge to this feature.

Other changes

We've synced up the changes that were made to the official go net/smtp package with our own copy. So this way go-mail is fully in sync with the official go package again.

What's Changed

• Sync upstream changes to net/smtp by @wneessen in Sync upstream changes to net/smtp #127
• Adding WithDialContextFunc client option by @sters in Adding WithDialContextFunc client option #128
• add Oauth2 support by @drakkan in add Oauth2 support #130
• Preparation for the v0.4.0 release: by @wneessen in Preparation for the v0.4.0 release: #131
• oauth2: add more test cases by @drakkan in oauth2: add more test cases #132

New Contributors

• @sters made their first contribution in Adding WithDialContextFunc client option #128
• @drakkan made their first contribution in add Oauth2 support #130

Full Changelog: v0.3.9...v0.4.0

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This discussion was created from the release v0.4.0: Custom dial contexts and OAUTH2 support.