CI: add snap package publish job

.github/workflows/CI.yml

@@ -2,6 +2,9 @@ name: CI
 
 on: [push, pull_request, workflow_dispatch]
 
+env:
+  SNAPCRAFT_STORE_CREDENTIALS: ${{secrets.SNAPCRAFT_LOGIN}}
+
 jobs:
   build:
     runs-on: ubuntu-22.04
@@ -126,3 +129,32 @@ jobs:
         dotnet fantomas .
         git diff --exit-code
 
+  publish_snap:
+    needs:
+    - run_snap
+    - integration_tests
+    - conventions
+
+    runs-on: ubuntu-22.04
+    steps:
+    - uses: actions/download-artifact@v3
+      name: Download artifact
+      with:
+        name: snap
+
+    - name: Unzip & upload snap
+      run: |
+        zip -r snap.zip .
+
+    - name: Install snapcraft
+      run: |
+        sudo snap install --classic snapcraft
+
+    - name: Log into snapcraft
+      run: |
+        snapcraft login
+
+    - name: Upload to SnapStore
+      run: |
+        snapcraft upload *.snap --release=beta
+