ci: add ci for release helm chart (#121)

host Helm chart on GitHub pages.
diff --git a/.github/actions/chart-releaser-action b/.github/actions/chart-releaser-action
new file mode 160000
index 0000000..6eec360
--- /dev/null
+++ b/.github/actions/chart-releaser-action
@@ -0,0 +1 @@
+Subproject commit 6eec360873ca10c8e462c87ad50c38d1a4332638
diff --git a/.github/actions/setup-helm b/.github/actions/setup-helm
new file mode 160000
index 0000000..feeafa6
--- /dev/null
+++ b/.github/actions/setup-helm
@@ -0,0 +1 @@
+Subproject commit feeafa615201d17b5efbb26af053541ebb8c3677
diff --git a/.github/workflows/release.yaml b/.github/workflows/release.yaml
new file mode 100644
index 0000000..792d425
--- /dev/null
+++ b/.github/workflows/release.yaml
@@ -0,0 +1,37 @@
+name: Release Charts
+
+on:
+  push:
+    branches:
+      - main
+
+jobs:
+  release:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v2
+        with:
+          fetch-depth: 0
+
+      - name: Configure Git
+        run: |
+          git config user.name "$GITHUB_ACTOR"
+          git config user.email "$GITHUB_ACTOR@users.noreply.github.com"
+
+      - name: Install Helm
+        uses: ./.github/actions/setup-helm
+        with:
+          version: v3.4.0
+
+      - name: Add Helm repo
+        run: |
+          helm repo add bitnami https://charts.bitnami.com/bitnami
+          helm repo add apisix https://charts.apiseven.com
+
+      - name: Run chart-releaser
+        uses: ./.github/actions/chart-releaser-action
+        with:
+          charts_dir: .
+        env:
+          CR_TOKEN: "${{ secrets.GITHUB_TOKEN }}"
diff --git a/.gitmodules b/.gitmodules
index 320e730..07d6be6 100644
--- a/.gitmodules
+++ b/.gitmodules
@@ -2,3 +2,9 @@
 	path = .github/actions/setup-kind
 	url = https://github.com/engineerd/setup-kind.git
 	branch = v0.5.0
+[submodule ".github/actions/setup-helm"]
+	path = .github/actions/setup-helm
+	url = https://github.com/Azure/setup-helm.git
+[submodule ".github/actions/chart-releaser-action"]
+	path = .github/actions/chart-releaser-action
+	url = https://github.com/helm/chart-releaser-action.git