This PR fixes the examples test so that all YAML manifests under
examples directory are assured to be working under 1.25.
The content/js/examples/examples_test.go is out-dated and it is blocking
the `go mod tidy` run unfortunately. So this PR removes it.
This PR updates the go.mod file so that tests of the example manifests
are run against the 1.20 branch. The missing test cases for newly added
examples are also added. To perform tests on your local machine, run the
following command on the root of your local clone:
```
go test k8s.io/website/content/en/examples
```
Qiming Teng
Qiming Teng