CI GA: Update hercules_charts.yml

.github/workflows/hercules_charts.yml

@@ -1,20 +1,20 @@
+name: Hercules Insights, charts generated by src-d/hercules
+
 on:
   push:
-    branches:
-    - master
+    branches: [ "master" ]
   schedule:
   - cron: "0 5 * * *"
 
 jobs:
   hercules-charts:
     runs-on: ubuntu-latest
-    name: Hercules Insights, charts generated by src-d/hercules
     steps:
       - uses: actions/checkout@master
         with:
           fetch-depth: 0
       - name: Hercules Insights
-        uses: src-d/hercules@latest
+        uses: src-d/hercules@master
         # with:
           # # hercules command line arguments
           # args: # optional, default is --burndown --burndown-people --devs --couples