Upgrade to operator-sdk v1.3.0

Closes #266

I gradually bumped from v1.0.0 (default) to 1.3.0
(1.1.0 didn't have impact on us)
https://sdk.operatorframework.io/docs/upgrading-sdk-version/
Operator SDK uses v0.20.0. **Dependabot failed** because it bumps always one of the three packages that needs to be bumped
(viz my comment)

missing zapr v0.4.0 caused failing tests (missing interface in default zapr v0.1.0 caused runtime errors of logr v0.4.0)
Both zapr and logr must be bumped together

PROJECT

@@ -8,4 +8,5 @@ resources:
   version: v1beta1
 version: 3-alpha
 plugins:
-  go.sdk.operatorframework.io/v2-alpha: {}
+  manifests.sdk.operatorframework.io/v2: {}
+  scorecard.sdk.operatorframework.io/v2: {}

go.mod

@@ -5,16 +5,20 @@ go 1.13
 require (
 	github.com/AbsaOSS/gopkg v0.0.1
 	github.com/ghodss/yaml v1.0.0
-	github.com/go-logr/logr v0.1.0
+	github.com/go-logr/logr v0.4.0
+	github.com/go-logr/zapr v0.4.0 // indirect
 	github.com/infobloxopen/infoblox-go-client v1.1.0
 	github.com/lixiangzhong/dnsutil v0.0.0-20191203032812-75ad39d2945a
 	github.com/miekg/dns v1.1.38
 	github.com/onsi/ginkgo v1.14.2 // indirect
 	github.com/prometheus/client_golang v1.9.0
 	github.com/stretchr/testify v1.7.0
-	k8s.io/api v0.18.8
-	k8s.io/apimachinery v0.18.8
-	k8s.io/client-go v0.18.8
-	sigs.k8s.io/controller-runtime v0.6.2
+
+	// operator sdk v0.20.2; always bump together
+	k8s.io/api v0.20.2
+	k8s.io/apimachinery v0.20.2
+	k8s.io/client-go v0.20.2
+
+	sigs.k8s.io/controller-runtime v0.6.4
 	sigs.k8s.io/external-dns v0.7.6
 )