FIX: Slack channel override when using a secretRef for the webhook

[jescarri]

Related to: #458

Config file:

namespace: kyverno
slack:
  channels:
    - channel: kyverno-reports1
      customFields:
        cluster: ACluster
      filter:
        namespaces:
          include:
          - foo
          - bar
        policies:
          include:
          - testpolicy
        priorities:
          include: warning
      name: team1
      secretRef: kyverno-policy-reporter-data
      skipExistingOnStartup: false
      sources:
      - kyverno
    - channel: kyverno-reports2
      customFields:
        cluster: ACluster
      filter:
        namespaces:
          include:
          - tes1
        policies:
          include:
          - testPolicy
        priorities:
          include: warning
      name: team2
      secretRef: kyverno-policy-reporter-data
      skipExistingOnStartup: false
      sources:
      - kyverno

output

1.7207403643162174e+09	info	API BasicAuth enabled
1.7207403643356915e+09	info	team1 configured
1.7207403643685389e+09	info	team2 configured
1.7207403643687537e+09	info	start client	{"worker": 5}
1.7207403644691234e+09	info	informer sync completed
1.7207403647018857e+09	info	team1: PUSH OK
1.7207403647848663e+09	info	team2: PUSH OK
1.720740364784887e+09	info	team2: PUSH OK

[coveralls]

Pull Request Test Coverage Report for Build 9899859141

Details

• 2 of 2 (100.0%) changed or added relevant lines in 1 file are covered.
• 2 unchanged lines in 1 file lost coverage.
• Overall coverage decreased (-0.03%) to 89.604%

---

Files with Coverage Reduction	New Missed Lines	%
pkg/config/target_factory.go	2	96.48%

Totals
Change from base Build 9870395492:	-0.03%
Covered Lines:	5318
Relevant Lines:	5935

---

💛 - Coveralls