downgrade package to make tests work

newer version removed SetBinariesPath option which made test fail

Author: jamesgoodhouse

Diff for: go.mod

@@ -3,7 +3,7 @@ module github.com/jamesgoodhouse/cert-manager-webhook-namecheap
 go 1.16
 
 require (
-	github.com/jetstack/cert-manager v1.5.2
+	github.com/jetstack/cert-manager v1.4.4
 	github.com/namecheap/go-namecheap-sdk/v2 v2.0.2
 	k8s.io/apiextensions-apiserver v0.22.1
 	k8s.io/apimachinery v0.22.1