Specify Codecov version to work around codecov/codecov-action#1487 (#1441)

* Specify Codecov version to work around codecov/codecov-action#1487

* Try with v0.7.1

---------

Co-authored-by: Keith Beattie <[email protected]>

Author: lbianchi-lbl

.github/workflows/core.yml

@@ -152,6 +152,9 @@ jobs:
           # but does require token for other workflows e.g. merge to `main`
           # see https://github.com/codecov/codecov-action/issues/1274#issuecomment-1934437359
           token: ${{ secrets.CODECOV_TOKEN }}
+          # pinning version after v0.7.0 broke tokenless upload
+          # see codecov/codecov-action#1487
+          version: v0.7.1
 
   build-docs:
     name: Build Sphinx docs