Update go version to 1.18

[sasagarw]

Is your feature request related to a problem? Please describe.
Earlier go version produces breaking changes. The workflow is running 1.18 whereas repo is using 1.15, this creates breaking run of workflow because 1.18 uses go install instead of go get. Even kubebuilder is breaking since we should setup test env using make targets.

Describe the solution you'd like
Update go to 1.18 and use make targets for setting up test env.

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