Implements an informer for metrics-api types

This patch is for improving scalability of metrics data.
It does that by implementing an informer/lister for the
metrics-api data. This change will  cache metrics data
and avoid retrieving metrics data with directly from the
api-server, with each update.

Other addition includes
- Files for scale testing with project KWOK

Author: vladimirvivien

.github/workflows/release.yaml

@@ -11,16 +11,16 @@ jobs:
     runs-on: ubuntu-latest
     steps:
     - name: Checkout
-      uses: actions/checkout@master
+      uses: actions/checkout@v3
     - name: Set up Go
-      uses: actions/setup-go@master
+      uses: actions/setup-go@v4
       with:
-        go-version: 1.20
+        go-version: 'stable'
     - name: Binary release
-      uses: goreleaser/goreleaser-action@v2
+      uses: goreleaser/goreleaser-action@v4
       with:
         version: latest
-        args: release --rm-dist
+        args: release --clean
       env:
         GITHUB_TOKEN: ${{ secrets.RELEASER_SECRET }}
     - name: Update new version in krew-index

README.md

@@ -45,7 +45,7 @@ brew install ktop
 The binary is relased as an OCI container at `ghcr.io/vladimirvivien/ktop`.
 If you have a container runtime installed (Docker for instance), you launch ktop as shown below:
 
-``
+```
 export KUBECONFIG=/home/user/.kube/config
 docker run --network=host --rm --platform="linux/arm64" -it -v $KUBECONFIG:/config -e KUBECONFIG=/config -e TERM=xterm-256color ghcr.io/vladimirvivien/ktop:latest
 ```

hack/kwok/kwok-deployments.yaml

@@ -0,0 +1,135 @@
+apiVersion: apps/v1
+kind: Deployment
+metadata:
+  name: fake-web-1
+  namespace: default
+spec:
+  replicas: 100
+  selector:
+    matchLabels:
+      app: fake-web-1
+  template:
+    metadata:
+      labels:
+        app: fake-web-1
+    spec:
+      affinity:
+        nodeAffinity:
+          requiredDuringSchedulingIgnoredDuringExecution:
+            nodeSelectorTerms:
+              - matchExpressions:
+                  - key: type
+                    operator: In
+                    values:
+                      - kwok
+      # A taints was added to an automatically created Node.
+      # You can remove taints of Node or add this tolerations.
+      tolerations:
+        - key: "kwok.x-k8s.io/node"
+          operator: "Exists"
+          effect: "NoSchedule"
+      containers:
+        - name: fake-container
+          image: fake-image
+---
+apiVersion: apps/v1
+kind: Deployment
+metadata:
+  name: fake-web-2
+  namespace: default
+spec:
+  replicas: 50
+  selector:
+    matchLabels:
+      app: fake-web-2
+  template:
+    metadata:
+      labels:
+        app: fake-web-2
+    spec:
+      affinity:
+        nodeAffinity:
+          requiredDuringSchedulingIgnoredDuringExecution:
+            nodeSelectorTerms:
+              - matchExpressions:
+                  - key: type
+                    operator: In
+                    values:
+                      - kwok
+      # A taints was added to an automatically created Node.
+      # You can remove taints of Node or add this tolerations.
+      tolerations:
+        - key: "kwok.x-k8s.io/node"
+          operator: "Exists"
+          effect: "NoSchedule"
+      containers:
+        - name: fake-container
+          image: fake-image
+---
+apiVersion: apps/v1
+kind: Deployment
+metadata:
+  name: fake-backend-1
+  namespace: default
+spec:
+  replicas: 25
+  selector:
+    matchLabels:
+      app: fake-backend-1
+  template:
+    metadata:
+      labels:
+        app: fake-backend-1
+    spec:
+      affinity:
+        nodeAffinity:
+          requiredDuringSchedulingIgnoredDuringExecution:
+            nodeSelectorTerms:
+              - matchExpressions:
+                  - key: type
+                    operator: In
+                    values:
+                      - kwok
+      # A taints was added to an automatically created Node.
+      # You can remove taints of Node or add this tolerations.
+      tolerations:
+        - key: "kwok.x-k8s.io/node"
+          operator: "Exists"
+          effect: "NoSchedule"
+      containers:
+        - name: fake-container
+          image: fake-image
+---
+apiVersion: apps/v1
+kind: Deployment
+metadata:
+  name: fake-backend-2
+  namespace: default
+spec:
+  replicas: 10
+  selector:
+    matchLabels:
+      app: fake-backend-2
+  template:
+    metadata:
+      labels:
+        app: fake-backend-2
+    spec:
+      affinity:
+        nodeAffinity:
+          requiredDuringSchedulingIgnoredDuringExecution:
+            nodeSelectorTerms:
+              - matchExpressions:
+                  - key: type
+                    operator: In
+                    values:
+                      - kwok
+      # A taints was added to an automatically created Node.
+      # You can remove taints of Node or add this tolerations.
+      tolerations:
+        - key: "kwok.x-k8s.io/node"
+          operator: "Exists"
+          effect: "NoSchedule"
+      containers:
+        - name: fake-container
+          image: fake-image