[CI] Only push metrics from master

.github/workflows/main.yml

@@ -191,6 +191,7 @@ jobs:
           |
           cd $PWD/extras/test/ci
           ./parse_size.sh ${{ matrix.id }}
+          cat size_${{ steps.short-hash.outputs.short_sha }}_${{ steps.split.outputs._0 }}-${{ steps.split.outputs._1 }}-${{ steps.split.outputs._2 }}.csv
       
       - name: Extract short commit hash
         id: short-hash
@@ -205,6 +206,7 @@ jobs:
   metrics:
     runs-on: ubuntu-latest
     needs: build
+    if: github.ref == 'refs/heads/master'
     steps:
       - name: Set up SSH
         run: |