CI: update actions/{up,down}load-artifact (#379)

Author: newAM

.github/workflows/ci.yml

@@ -81,7 +81,7 @@ jobs:
       - run: |
           cargo test -p testsuite --target thumbv7em-none-eabi --bins --locked --no-run
       - name: Upload test binaries
-        uses: actions/upload-artifact@v3
+        uses: actions/upload-artifact@v4
         with:
           name: test-bins
           if-no-files-found: error
@@ -110,7 +110,7 @@ jobs:
         run: probe-rs --version
       - name: List probes
         run: probe-rs list
-      - uses: newAM/download-artifact@4202241ccada6f83f838525a8af979a4ec900a49
+      - uses: actions/download-artifact@v4
         with:
           name: test-bins
           path: bins