Add CI/CD pipeline to publish on charmhub.io (#95)

* Add CI/CD pipeline to publish on charmhub.io

* generated and configured new CHARMHUB_TOKEN

* Do not call ci.yaml on merge to trunk

The release.yaml will run ci.yaml tests after merging and before publishing.

.github/workflows/ci.yaml

@@ -1,9 +1,6 @@
 name: Charmed Operator Tests
 on:
   workflow_call:
-  push:
-    branches:
-      - main
   pull_request:
 
 jobs:
@@ -12,4 +9,4 @@ jobs:
   unit:
     uses: ./.github/workflows/unit.yaml
   integration:
-    uses: ./.github/workflows/integration.yaml
+    uses: ./.github/workflows/integration.yaml

.github/workflows/release.yaml

@@ -0,0 +1,49 @@
+name: Release to latest/edge
+
+on:
+  push:
+    branches:
+      - main
+
+jobs:
+  lib-check:
+    name: Check libraries
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v3
+        with:
+          fetch-depth: 0
+      - name: Check libs
+        uses: canonical/charming-actions/[email protected]
+        with:
+          # FIXME: CHARMHUB_TOKEN will expire in 2024-01-20
+          # NOTE: CHARMHUB_TOKEN is only allowed in latest/edge, latest/candidate
+          credentials: "${{ secrets.CHARMHUB_TOKEN }}"
+          github-token: "${{ secrets.GITHUB_TOKEN }}"
+
+  ci-tests:
+    needs:
+      - lib-check
+    uses: ./.github/workflows/ci.yaml
+
+  release-to-charmhub:
+    name: Release to CharmHub
+    needs:
+      - lib-check
+      - ci-tests
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v3
+        with:
+          fetch-depth: 0
+      - name: Select charmhub channel
+        uses: canonical/charming-actions/[email protected]
+        id: channel
+      - name: Upload charm to charmhub
+        uses: canonical/charming-actions/[email protected]
+        with:
+          credentials: "${{ secrets.CHARMHUB_TOKEN }}"
+          github-token: "${{ secrets.GITHUB_TOKEN }}"
+          channel: "${{ steps.channel.outputs.name }}"