use istio client-go library instead of knative (#1661)

use istio client-go library instead of knative
bump kubernetes dependency version
change code coverage to codecov

vendor/sigs.k8s.io/controller-runtime/CONTRIBUTING.md

@@ -0,0 +1,27 @@
+# Contributing guidelines
+
+## Sign the CLA
+
+Kubernetes projects require that you sign a Contributor License Agreement (CLA) before we can accept your pull requests.
+  
+Please see https://git.k8s.io/community/CLA.md for more info
+
+## Contributing steps
+
+1. Submit an issue describing your proposed change to the repo in question.
+1. The [repo owners](OWNERS) will respond to your issue promptly.
+1. If your proposed change is accepted, and you haven't already done so, sign a Contributor License Agreement (see details above).
+1. Fork the desired repo, develop and test your code changes.
+1. Submit a pull request.
+
+## Test locally
+
+1. Setup tools
+    ```bash
+    $ curl -sfL https://install.goreleaser.com/github.com/golangci/golangci-lint.sh | sh -s -- -b $(go env GOPATH)/bin v1.17.1
+    ```
+1. Test
+    ```bash
+    GO111MODULE=on TRACE=1 ./hack/check-everything.sh
+    ```
+