chore: add linter, tepmlate validation CI

.github/workflows/testing.yaml

@@ -0,0 +1,24 @@
+name: CI
+
+on:
+  push:
+    branches:
+      - master
+  pull_request:
+
+concurrency:
+  # In master we want to run for every commit, in other branches — only for the last one
+  group: ${{
+    ( github.ref == 'refs/heads/master' && format('{0}/{1}/{2}', github.workflow, github.ref, github.sha) )
+    ||
+    format('{0}/{1}', github.workflow, github.ref) }}
+  cancel-in-progress: true
+
+jobs:
+  lint:
+    runs-on: ubuntu-latest
+    steps:
+      - run: curl https://raw.githubusercontent.com/helm/helm/main/scripts/get-helm-3 | bash
+      - uses: actions/checkout@v4
+      - run: helm lint
+      - run: helm template my-release .