enable electron builder signing again (#2317)

.github/workflows/build.yml

@@ -182,8 +182,6 @@ jobs:
           echo "${{ env.pythonLocation }}/bin" >> $GITHUB_PATH
       - shell: bash
         run: |
-          # disable electron-builder signing and make dist
-          export CSC_IDENTITY_AUTO_DISCOVERY=false
           make dist
         env:
           BUILD: osx