Revert "Bump codecov/codecov-action from 3 to 4 (#100)" (#101)

This reverts commit 1390e75.

Author: jishnub

.github/workflows/ci.yml

@@ -65,6 +65,6 @@ jobs:
       - uses: julia-actions/julia-buildpkg@v1
       - uses: julia-actions/julia-runtest@v1
       - uses: julia-actions/julia-processcoverage@v1
-      - uses: codecov/codecov-action@v4
+      - uses: codecov/codecov-action@v3
         with:
           file: lcov.info

.github/workflows/downstream.yml

@@ -72,6 +72,6 @@ jobs:
             exit(0)  # Exit immediately, as a success
           end
       - uses: julia-actions/julia-processcoverage@v1
-      - uses: codecov/codecov-action@v4
+      - uses: codecov/codecov-action@v3
         with:
           files: lcov.info