feat: always store namespace in func.yaml and warn if current ns & func.yaml ns is different

[gauron99]

Changes

changes to func deploy

• store namespace to func.yaml on first deployment (from current namespace)
• if namespace is not specified via CLI and is different from func.yaml print warning explaining this
  (ex: func.yaml->namespace = default && oc->namespace = myns -> print warning where func is deployed)
• if namespace is specified via CLI, assume user knows what hes doing, do nothing

update

• add fake KUBECONFIG to all the tests in deploy_test.go
• replace context.TODO with context.Background in deploy_test.go
• print warning to stderr

Fixes #1084

[matejvasek]

@gauron99 the unitests are failing

[matejvasek]

you need to add
defer WithEnvVar(t, "KUBECONFIG", fmt.Sprintf("%s/testdata/kubeconfig_deploy_namespace", cwd()))()
into Test_runDeploy.

[codecov]

Codecov Report

Merging #1118 (20ec1f8) into main (b1fd9f7) will increase coverage by 0.03%.
The diff coverage is 62.50%.

@@            Coverage Diff             @@
##             main    #1118      +/-   ##
==========================================
+ Coverage   45.89%   45.92%   +0.03%     
==========================================
  Files          65       65              
  Lines        8701     8717      +16     
==========================================
+ Hits         3993     4003      +10     
- Misses       4321     4325       +4     
- Partials      387      389       +2     

Impacted Files	Coverage Δ
cmd/deploy.go	59.26% <62.50%> (+0.13%)	⬆️

[matejvasek]

Why we cannot use command args?

[gauron99]

When i used cmd.SetArgs i got an error Got error 'unknown flag: --namespace' as it is a global flag, using viper worked to fix it

[zroubalik]

/lgtm

/hold for others

[knative-prow]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: gauron99, zroubalik

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[lance]

/lgtm
/unhold