Revert "Bump codecov/codecov-action from 3 to 5 (#665)"

This reverts commit 57b9084.

Author: jishnub

.github/workflows/ci.yml

@@ -61,6 +61,6 @@ jobs:
       - uses: julia-actions/julia-buildpkg@v1
       - uses: julia-actions/julia-runtest@v1
       - uses: julia-actions/julia-processcoverage@v1
-      - uses: codecov/codecov-action@v5
+      - uses: codecov/codecov-action@v3
         with:
           file: lcov.info

.github/workflows/downstream.yml

@@ -74,6 +74,6 @@ jobs:
             exit(0)  # Exit immediately, as a success
           end
       - uses: julia-actions/julia-processcoverage@v1
-      - uses: codecov/codecov-action@v5
+      - uses: codecov/codecov-action@v3
         with:
           files: lcov.info