Update Go mod for Go 1.21 support

This change updates go.mod for Go 1.21 support. This is needed to
consume the github.com/containernetworking/plugins v1.4.1 dependency
updates.

Signed-off-by: Austin Vazquez <macedonv@amazon.com>

go.mod

@@ -1,13 +1,20 @@
 module github.com/awslabs/tc-redirect-tap
 
-go 1.11
+go 1.21
 
 require (
 	github.com/containernetworking/cni v1.1.2
 	github.com/containernetworking/plugins v1.4.0
 	github.com/hashicorp/go-multierror v1.1.1
-	github.com/onsi/ginkgo v1.16.5 // indirect
 	github.com/stretchr/testify v1.9.0
 	github.com/vishvananda/netlink v1.2.1-beta.2
 	golang.org/x/sys v0.18.0
 )
+
+require (
+	github.com/davecgh/go-spew v1.1.1 // indirect
+	github.com/hashicorp/errwrap v1.0.0 // indirect
+	github.com/pmezard/go-difflib v1.0.0 // indirect
+	github.com/vishvananda/netns v0.0.4 // indirect
+	gopkg.in/yaml.v3 v3.0.1 // indirect
+)