chore(deps): bump github.com/alecthomas/kingpin/v2 from 2.3.2 to 2.4.0

Bumps [github.com/alecthomas/kingpin/v2](https://github.com/alecthomas/kingpin) from 2.3.2 to 2.4.0.
- [Release notes](https://github.com/alecthomas/kingpin/releases)
- [Commits](https://github.com/alecthomas/kingpin/compare/v2.3.2...v2.4.0)

go.mod

@@ -3,7 +3,7 @@ module gitlab.com/unboundsoftware/cron-checker
 go 1.15
 
 require (
-	github.com/alecthomas/kingpin/v2 v2.3.2
+	github.com/alecthomas/kingpin/v2 v2.4.0
 	github.com/multiplay/go-slack v0.0.0-20200412115802-09e9e2b93fe2
 	github.com/robfig/cron v1.2.0
 	github.com/rogpeppe/go-internal v1.11.0 // indirect

go.sum

@@ -1,7 +1,7 @@
 cloud.google.com/go/compute/metadata v0.2.0/go.mod h1:zFmK7XCadkQkj6TtorcaGlCW1hT1fIilQDwofLpJ20k=
 github.com/NYTimes/gziphandler v0.0.0-20170623195520-56545f4a5d46/go.mod h1:3wb06e3pkSAbeQ52E9H9iFoQsEEwGN64994WTCIhntQ=
-github.com/alecthomas/kingpin/v2 v2.3.2 h1:H0aULhgmSzN8xQ3nX1uxtdlTHYoPLu5AhHxWrKI6ocU=
-github.com/alecthomas/kingpin/v2 v2.3.2/go.mod h1:0gyi0zQnjuFk8xrkNKamJoyUo382HRL7ATRpFZCw6tE=
+github.com/alecthomas/kingpin/v2 v2.4.0 h1:f48lwail6p8zpO1bC4TxtqACaGqHYA22qkHjHpqDjYY=
+github.com/alecthomas/kingpin/v2 v2.4.0/go.mod h1:0gyi0zQnjuFk8xrkNKamJoyUo382HRL7ATRpFZCw6tE=
 github.com/alecthomas/units v0.0.0-20211218093645-b94a6e3cc137 h1:s6gZFSlWYmbqAuRjVTiNNhvNRfY2Wxp9nhfyel4rklc=
 github.com/alecthomas/units v0.0.0-20211218093645-b94a6e3cc137/go.mod h1:OMCwj8VM1Kc9e19TLln2VL61YJF0x1XFtfdL4JdbSyE=
 github.com/armon/go-socks5 v0.0.0-20160902184237-e75332964ef5/go.mod h1:wHh0iHkYZB8zMSxRWpUBQtwG5a7fFgvEO+odwuTv2gs=