Bump github.com/xhit/go-simple-mail/v2 from 2.13.0 to 2.15.0

Bumps [github.com/xhit/go-simple-mail/v2](https://github.com/xhit/go-simple-mail) from 2.13.0 to 2.15.0.
- [Release notes](https://github.com/xhit/go-simple-mail/releases)
- [Commits](https://github.com/xhit/go-simple-mail/compare/v2.13.0...v2.15.0)

---
updated-dependencies:
- dependency-name: github.com/xhit/go-simple-mail/v2
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>

go.sum

@@ -1628,8 +1628,8 @@ github.com/xeipuuv/gojsonpointer v0.0.0-20190905194746-02993c407bfb/go.mod h1:N2
 github.com/xeipuuv/gojsonreference v0.0.0-20180127040603-bd5ef7bd5415 h1:EzJWgHovont7NscjpAxXsDA8S8BMYve8Y5+7cuRE7R0=
 github.com/xeipuuv/gojsonreference v0.0.0-20180127040603-bd5ef7bd5415/go.mod h1:GwrjFmJcFw6At/Gs6z4yjiIwzuJ1/+UwLxMQDVQXShQ=
 github.com/xeipuuv/gojsonschema v1.2.0/go.mod h1:anYRn/JVcOK2ZgGU+IjEV4nwlhoK5sQluxsYJ78Id3Y=
-github.com/xhit/go-simple-mail/v2 v2.13.0 h1:OANWU9jHZrVfBkNkvLf8Ww0fexwpQVF/v/5f96fFTLI=
-github.com/xhit/go-simple-mail/v2 v2.13.0/go.mod h1:b7P5ygho6SYE+VIqpxA6QkYfv4teeyG4MKqB3utRu98=
+github.com/xhit/go-simple-mail/v2 v2.15.0 h1:qMXeqcZErUW/Dw6EXxmPuxHzVI8MdxWnEnu2xcisohU=
+github.com/xhit/go-simple-mail/v2 v2.15.0/go.mod h1:b7P5ygho6SYE+VIqpxA6QkYfv4teeyG4MKqB3utRu98=
 github.com/xiang90/probing v0.0.0-20190116061207-43a291ad63a2/go.mod h1:UETIi67q53MR2AWcXfiuqkDkRtnGDLqkBTpCHuJHxtU=
 github.com/xlab/treeprint v1.1.0/go.mod h1:gj5Gd3gPdKtR1ikdDK6fnFLdmIS0X30kTTuNd/WEJu0=
 github.com/xo/terminfo v0.0.0-20220910002029-abceb7e1c41e h1:JVG44RsyaB9T2KIHavMF/ppJZNG9ZpyihvCd0w101no=