Test latest (1.22) and oldest supported (1.17) k8s version

.github/workflows/test.yml

@@ -1,3 +1,6 @@
+# This is a GitHub workflow defining a set of jobs with a set of steps.
+# ref: https://docs.github.com/en/actions/learn-github-actions/workflow-syntax-for-github-actions
+#
 name: Tests
 
 on:
@@ -24,13 +27,20 @@ jobs:
       fail-fast: false
       matrix:
         k3s-channel:
-        - v1.19
-        helm-version:
-        - v3.5.0
+        # Available channels: https://github.com/k3s-io/k3s/blob/HEAD/channel.yaml
+        - latest
         test:
         - main
         - auth
         - helm
+        include:
+          # Chart.yaml contains the chart's oldest supported k8s version, we
+          # test against that. We also test against the oldest known supported
+          # helm cli version which isn't documented anywhere, but is currently
+          # at 3.5.0.
+          - k3s-channel: "v1.17"
+            helm-version: v3.5.0
+            test: helm
     steps:
       - uses: actions/checkout@v2
         with:
@@ -39,7 +49,7 @@ jobs:
 
       - uses: jupyterhub/action-k3s-helm@v1
         with:
-          k3s-version: ${{ matrix.k3s-version }}
+          k3s-channel: ${{ matrix.k3s-channel }}
           helm-version: ${{ matrix.helm-version }}
           metrics-enabled: false
           traefik-enabled: false