chore(deps): update module github.com/alecthomas/kong to v1.8.1 (#503)

Co-authored-by: renovate[bot] <29139614+renovate[bot]@users.noreply.github.com>

Author: renovate[bot]

_examples/server/go.mod

@@ -4,7 +4,7 @@ go 1.13
 
 require (
 	github.com/alecthomas/colour v0.1.0
-	github.com/alecthomas/kong v1.7.0
+	github.com/alecthomas/kong v1.8.1
 	github.com/chzyer/readline v1.5.1
 	github.com/chzyer/test v1.0.0 // indirect
 	github.com/flynn/go-shlex v0.0.0-20150515145356-3f9db97f8568 // indirect

_examples/server/go.sum

@@ -24,6 +24,8 @@ github.com/alecthomas/kong v1.6.1 h1:/7bVimARU3uxPD0hbryPE8qWrS3Oz3kPQoxA/H2NKG8
 github.com/alecthomas/kong v1.6.1/go.mod h1:p2vqieVMeTAnaC83txKtXe8FLke2X07aruPWXyMPQrU=
 github.com/alecthomas/kong v1.7.0 h1:MnT8+5JxFDCvISeI6vgd/mFbAJwueJ/pqQNzZMsiqZE=
 github.com/alecthomas/kong v1.7.0/go.mod h1:p2vqieVMeTAnaC83txKtXe8FLke2X07aruPWXyMPQrU=
+github.com/alecthomas/kong v1.8.1 h1:6aamvWBE/REnR/BCq10EcozmcpUPc5aGI1lPAWdB0EE=
+github.com/alecthomas/kong v1.8.1/go.mod h1:p2vqieVMeTAnaC83txKtXe8FLke2X07aruPWXyMPQrU=
 github.com/alecthomas/repr v0.1.0/go.mod h1:2kn6fqh/zIyPLmm3ugklbEi5hg5wS435eygvNfaDQL8=
 github.com/alecthomas/repr v0.4.0/go.mod h1:Fr0507jx4eOXV7AlPV6AVZLYrLIuIeSOWtW57eE/O/4=
 github.com/anmitsu/go-shlex v0.0.0-20161002113705-648efa622239 h1:kFOfPq6dUM1hTo4JG6LR5AXSUEsOjtdm0kw0FtQtMJA=