feat: added versioned validation and installation of controller-gen

[yashvardhan-kukreja]

Signed-off-by: Yashvardhan Kukreja yash.kukreja.98@gmail.com

Related issue

closes #1617

What type of PR is this

/kind feature
/kind bug

Proposed changes

From now on, whenever the user will run make controller-gen, it will be made sure that they end up specifically with v0.4.0 (currently) of controller-gen.

Checklist

• I have read the contributing guidelines.
• I have added tests that prove my fix is effective or that my feature works.
• I have added or changed the documentation.

Further comments

Here's an example of it working:

1. User doesn't have controller-gen installed

► make controller-gen
controller-gen not found!
installing controller-gen v0.4.0...
make[1]: Entering directory '/home/yash1300/Projects/GoProjects/github.com/yashvardhan-kukreja/kyverno'
go: creating new go.mod: module tmp
go: found sigs.k8s.io/controller-tools/cmd/controller-gen in sigs.k8s.io/controller-tools v0.4.0
CONTROLLER_GEN=/home/yash1300/Projects/GoProjects/bin/controller-gen
make[1]: Leaving directory '/home/yash1300/Projects/GoProjects/github.com/yashvardhan-kukreja/kyverno'

2. User has controller-gen installed but with some different version (0.2.5 for eg:)

► make controller-gen
controller-gen Version: v0.2.5 found!
required controller-gen v0.4.0
installing controller-gen v0.4.0...
make[1]: Entering directory '/home/yash1300/Projects/GoProjects/github.com/yashvardhan-kukreja/kyverno'
go: creating new go.mod: module tmp
go: found sigs.k8s.io/controller-tools/cmd/controller-gen in sigs.k8s.io/controller-tools v0.4.0
CONTROLLER_GEN=/home/yash1300/Projects/GoProjects/bin/controller-gen
make[1]: Leaving directory '/home/yash1300/Projects/GoProjects/github.com/yashvardhan-kukreja/kyverno'

3. User has controller-gen v0.4.0 installed

► make controller-gen
make: Nothing to be done for 'controller-gen'.

[yashvardhan-kukreja]

ptal @realshuting

[realshuting]

lgtm