Bump github.com/peterbourgon/ff/v3 from 3.3.0 to 3.3.1

Bumps [github.com/peterbourgon/ff/v3](https://github.com/peterbourgon/ff) from 3.3.0 to 3.3.1.
- [Release notes](https://github.com/peterbourgon/ff/releases)
- [Commits](https://github.com/peterbourgon/ff/compare/v3.3.0...v3.3.1)

---
updated-dependencies:
- dependency-name: github.com/peterbourgon/ff/v3
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <[email protected]>

go.mod

@@ -3,7 +3,7 @@ module github.com/decke/smtprelay
 require (
 	github.com/chrj/smtpd v0.3.1
 	github.com/google/uuid v1.3.0
-	github.com/peterbourgon/ff/v3 v3.3.0
+	github.com/peterbourgon/ff/v3 v3.3.1
 	github.com/sirupsen/logrus v1.9.0
 	github.com/stretchr/testify v1.8.2
 	golang.org/x/crypto v0.8.0

go.sum

@@ -13,8 +13,8 @@ github.com/kr/pty v1.1.1/go.mod h1:pFQYn66WHrOpPYNljwOMqo10TkYh1fy3cYio2l3bCsQ=
 github.com/kr/text v0.1.0/go.mod h1:4Jbv+DJW3UT/LiOwJeYQe1efqtUx/iVham/4vfdArNI=
 github.com/kr/text v0.2.0 h1:5Nx0Ya0ZqY2ygV366QzturHI13Jq95ApcVaJBhpS+AY=
 github.com/kr/text v0.2.0/go.mod h1:eLer722TekiGuMkidMxC/pM04lWEeraHUUmBw8l2grE=
-github.com/peterbourgon/ff/v3 v3.3.0 h1:PaKe7GW8orVFh8Unb5jNHS+JZBwWUMa2se0HM6/BI24=
-github.com/peterbourgon/ff/v3 v3.3.0/go.mod h1:zjJVUhx+twciwfDl0zBcFzl4dW8axCRyXE/eKY9RztQ=
+github.com/peterbourgon/ff/v3 v3.3.1 h1:XSWvXxeNdgeppLNGGJEAOiXRdX2YMF/LuZfdnqQ1SNc=
+github.com/peterbourgon/ff/v3 v3.3.1/go.mod h1:zjJVUhx+twciwfDl0zBcFzl4dW8axCRyXE/eKY9RztQ=
 github.com/pkg/diff v0.0.0-20210226163009-20ebb0f2a09e/go.mod h1:pJLUxLENpZxwdsKMEsNbx1VGcRFpLqf3715MtcvvzbA=
 github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
 github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=