Bump github.com/alecthomas/kong from 0.2.12 to 0.2.15 (#160)

Bumps [github.com/alecthomas/kong](https://github.com/alecthomas/kong) from 0.2.12 to 0.2.15.
- [Release notes](https://github.com/alecthomas/kong/releases)
- [Commits](alecthomas/kong@v0.2.12...v0.2.15)

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

Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Author: dependabot[bot]

go.mod

@@ -3,7 +3,7 @@ module github.com/crazy-max/ftpgrab/v7
 go 1.15
 
 require (
-	github.com/alecthomas/kong v0.2.12
+	github.com/alecthomas/kong v0.2.15
 	github.com/crazy-max/gonfig v0.4.0
 	github.com/docker/go-units v0.4.0
 	github.com/go-gomail/gomail v0.0.0-20160411212932-81ebce5c23df

go.sum

@@ -6,8 +6,8 @@ github.com/Masterminds/sprig v2.16.0+incompatible h1:QZbMUPxRQ50EKAq3LFMnxddMu88
 github.com/Masterminds/sprig v2.16.0+incompatible/go.mod h1:y6hNFY5UBTIWBxnzTeuNhlNS5hqE0NB0E6fgfo2Br3o=
 github.com/PuerkitoBio/goquery v1.5.0 h1:uGvmFXOA73IKluu/F84Xd1tt/z07GYm8X49XKHP7EJk=
 github.com/PuerkitoBio/goquery v1.5.0/go.mod h1:qD2PgZ9lccMbQlc7eEOjaeRlFQON7xY8kdmcsrnKqMg=
-github.com/alecthomas/kong v0.2.12 h1:X3kkCOXGUNzLmiu+nQtoxWqj4U2a39MpSJR3QdQXOwI=
-github.com/alecthomas/kong v0.2.12/go.mod h1:kQOmtJgV+Lb4aj+I2LEn40cbtawdWJ9Y8QLq+lElKxE=
+github.com/alecthomas/kong v0.2.15 h1:HP3K1XuFn0wGSWFGVW67V+65tXw/Ht8FDYiLNAuX2Ug=
+github.com/alecthomas/kong v0.2.15/go.mod h1:kQOmtJgV+Lb4aj+I2LEn40cbtawdWJ9Y8QLq+lElKxE=
 github.com/andybalholm/cascadia v1.0.0 h1:hOCXnnZ5A+3eVDX8pvgl4kofXv2ELss0bKcqRySc45o=
 github.com/andybalholm/cascadia v1.0.0/go.mod h1:GsXiBklL0woXo1j/WYWtSYYC4ouU9PqHO0sqidkEA4Y=
 github.com/aokoli/goutils v1.0.1 h1:7fpzNGoJ3VA8qcrm++XEE1QUe0mIwNeLa02Nwq7RDkg=