Add a workflow to control Snap publications (#1176)

.github/workflows/release-snap.yml

@@ -0,0 +1,22 @@
+on:
+  workflow_dispatch:
+    inputs:
+      branch:
+        description: "The branch, tag or SHA to release from"
+        required: true
+        default: "master"
+
+jobs:
+  snap:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v2
+        with:
+          ref: ${{ github.event.inputs.branch }}
+      - uses: snapcore/action-build@v1
+        id: build
+      - uses: snapcore/action-publish@v1
+        with:
+          store_login: ${{ secrets.SNAP_STORE_LOGIN }}
+          snap: ${{ steps.build.outputs.snap }}
+          release: edge

.github/workflows/release.yml

@@ -17,6 +17,8 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v2
+        with:
+          ref: ${{ github.event.inputs.branch }}
       - uses: actions/setup-python@v2
         with:
           python-version: 3.9