fix(ci): correct SNAP_RELEASE_NAME

at some point we started adding v to release_name,
which lead to invalid tag path (tags/vv0.34.0)
this strips it out

.github/workflows/snapcraft.yml

@@ -5,17 +5,20 @@ on:
     inputs:
       manual_name:
         required: true
-        description: 'Release number to publish (without v prefix)'
-        default: '0.0.0'
+        description: 'Release number to publish'
+        default: 'v0.0.0'
   release:
     types: [published]
 
 jobs:
   publish:
     runs-on: ubuntu-latest
-    env:
-      SNAP_RELEASE_NAME: ${{ github.event.inputs.manual_name || github.event.release.name }}
     steps:
+      - name: Strip 'v' prefix
+        id: name
+        run: |
+          TAG=${{ github.event.inputs.manual_name || github.event.release.name }}
+          echo "SNAP_RELEASE_NAME=${TAG#v}" >> $GITHUB_ENV
       - name: Download .snap artifact
         uses: dsaltares/fetch-gh-release-asset@0efe227dedb360b09ea0e533795d584b61c461a9 # 0.06
         with: