helm: Fixed chart-test CI config.

Also added yaml lint config and chart_schema files from:
https://github.com/helm/chart-testing/tree/b060fc83f292a1ef7ea6f9db5a5834eb8a83b152/etc

These files are required by chart-test's "lint" command.
There does not appear to be any documentation about this.

Refer to the following GitHub issue for more information:
helm/chart-testing#138

.github/workflows/helm-chart-lint.yaml

@@ -28,10 +28,17 @@ jobs:
         uses: helm/[email protected]
 
       - name: Run chart-testing (lint)
-        run: ct lint --target-branch ${{ github.event.repository.default_branch }}
+        run: >
+          ct lint
+          --chart-dirs deploy/helm
+          --target-branch ${{ github.event.repository.default_branch }}
+          --lint-conf hack/ci/chart-test-lintconf
+          --chart-yaml-schema hack/ci/chart_schema.yaml
 
       - name: Create kind cluster
         uses: helm/[email protected]
 
       - name: Run chart-testing (install)
-        run: ct install
+        run: >
+          ct install
+          --chart-dirs deploy/helm

hack/ci/chart-test-lintconf.yaml

@@ -0,0 +1,43 @@
+---
+rules:
+  braces:
+    min-spaces-inside: 0
+    max-spaces-inside: 0
+    min-spaces-inside-empty: -1
+    max-spaces-inside-empty: -1
+  brackets:
+    min-spaces-inside: 0
+    max-spaces-inside: 0
+    min-spaces-inside-empty: -1
+    max-spaces-inside-empty: -1
+  colons:
+    max-spaces-before: 0
+    max-spaces-after: 1
+  commas:
+    max-spaces-before: 0
+    min-spaces-after: 1
+    max-spaces-after: 1
+  comments:
+    require-starting-space: true
+    min-spaces-from-content: 2
+  document-end: disable
+  document-start: disable           # No --- to start a file
+  empty-lines:
+    max: 2
+    max-start: 0
+    max-end: 0
+  hyphens:
+    max-spaces-after: 1
+  indentation:
+    spaces: consistent
+    indent-sequences: whatever      # - list indentation will handle both indentation and without
+    check-multi-line-strings: false
+  key-duplicates: enable
+  line-length: disable              # Lines can be any length
+  new-line-at-end-of-file: enable
+  new-lines:
+    type: unix
+  trailing-spaces: enable
+  truthy:
+    level: warning
+

hack/ci/chart_schema.yaml

@@ -0,0 +1,20 @@
+name: str()
+home: str()
+version: str()
+appVersion: any(str(), num())
+description: str()
+keywords: list(str(), required=False)
+sources: list(str(), required=False)
+maintainers: list(include('maintainer'), required=False)
+icon: str(required=False)
+engine: str(required=False)
+condition: str(required=False)
+tags: str(required=False)
+deprecated: bool(required=False)
+kubeVersion: str(required=False)
+annotations: map(str(), str(), required=False)
+---
+maintainer:
+  name: str()
+  email: str(required=False)
+  url: str(required=False)