Fix x/crypto vulnerability (#540)

Fix vulnerability that was detected by artifacthub scan

https://pkg.go.dev/golang.org/x/crypto@v0.0.0-20210616213533-5ff15b29337e?tab=versions is the latest at the moment of this change

Change was performed with

```
go mod edit -replace golang.org/x/crypto=golang.org/x/crypto@v0.0.0-20210616213533-5ff15b29337e
```

Resolves #539

Signed-off-by: Yury Tsarev <yury.tsarev@absa.africa>

go.mod

@@ -7,19 +7,19 @@ require (
 	github.com/ghodss/yaml v1.0.0
 	github.com/go-logr/logr v0.4.0
 	github.com/golang/mock v1.5.0
-	github.com/gruntwork-io/terratest v0.34.8
 	github.com/infobloxopen/infoblox-go-client v1.1.0
 	github.com/lixiangzhong/dnsutil v0.0.0-20191203032812-75ad39d2945a
 	github.com/miekg/dns v1.1.42
 	github.com/onsi/ginkgo v1.14.2 // indirect
 	github.com/prometheus/client_golang v1.10.0
 	github.com/rs/zerolog v1.21.0
 	github.com/stretchr/testify v1.7.0
-	gopkg.in/yaml.v2 v2.3.0
 	k8s.io/api v0.20.6
 	k8s.io/apiextensions-apiserver v0.20.2 // indirect
 	k8s.io/apimachinery v0.20.6
 	k8s.io/client-go v0.20.6
 	sigs.k8s.io/controller-runtime v0.7.2
 	sigs.k8s.io/external-dns v0.8.0
 )
+
+replace golang.org/x/crypto => golang.org/x/crypto v0.0.0-20210616213533-5ff15b29337e