Update NewestKubernetesVersion to 1.18.0-beta.2

[tstromberg]

To pass tests, this required updating the Kubernetes image logic.

The update to the Pause image version was particularly annoying, as it required plumbing the Kubernetes version into a few new locations.

[tstromberg]

/ok-to-test

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: tstromberg

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[minikube-pr-bot]

Error: running mkcmp: exit status 1

[medyagh]

lets make sure we push a preload tar for this version !

[codecov-io]

Codecov Report

Merging #6988 into master will not change coverage by %.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master    #6988   +/-   ##
=======================================
  Coverage   37.18%   37.18%           
=======================================
  Files         144      144           
  Lines        9055     9055           
=======================================
  Hits         3367     3367           
  Misses       5263     5263           
  Partials      425      425           

[minikube-pr-bot]

All Times Minikube (PR 6988): [ 67.819619 69.579902 62.717395]
All Times minikube: [ 65.621484 63.435351 65.705548]

Average minikube: 64.920794
Average Minikube (PR 6988): 66.705639

Averages Time Per Log

+----------------------+-----------+--------------------+
|         LOG          | MINIKUBE  | MINIKUBE (PR 6988) |
+----------------------+-----------+--------------------+
| minikube v           |  0.223829 |           0.217543 |
| Creating kvm2        | 40.970256 |          41.222363 |
| Preparing Kubernetes |  0.791678 |           0.791161 |
| Pulling images       |           |                    |
| Launching Kubernetes | 19.864450 |          21.223076 |
| Waiting for cluster  |  0.066933 |           0.062285 |
+----------------------+-----------+--------------------+

[priyawadhwa]

until I set up the automated tarball creation, you can run make upload-preloaded-images-tar on the branch to generate the preloaded tar for this version!

[tstromberg]

until I set up the automated tarball creation, you can run make upload-preloaded-images-tar on the branch to generate the preloaded tar for this version!

Thanks. There is now preload available for v1.18.0-beta.2: 36s startup time on macOS!