bump artifact actions to v4 (star-bnl#727)

Author: plexoos

.github/workflows/build-pull-request.yml

@@ -36,7 +36,7 @@ jobs:
           outputs: type=docker,dest=/tmp/star-sw-${{ env.STARENV }}.tar
 
       - name: Save built image for test jobs
-        uses: actions/upload-artifact@v3
+        uses: actions/upload-artifact@v4
         with:
           name: star-sw-${{ env.STARENV }}
           path: /tmp/star-sw-${{ env.STARENV }}.tar
@@ -54,7 +54,7 @@ jobs:
       STARENV: ${{ matrix.starenv }}-${{ matrix.compiler }}
     steps:
       - name: Download artifact
-        uses: actions/download-artifact@v3
+        uses: actions/download-artifact@v4
         with:
           name: star-sw-${{ env.STARENV }}
           path: /tmp
@@ -79,7 +79,7 @@ jobs:
       STARENV: root5-${{ matrix.compiler }}
     steps:
       - name: Download artifact
-        uses: actions/download-artifact@v3
+        uses: actions/download-artifact@v4
         with:
           name: star-sw-${{ env.STARENV }}
           path: /tmp
@@ -104,7 +104,7 @@ jobs:
       STARENV: root5-${{ matrix.compiler }}
     steps:
       - name: Download artifact
-        uses: actions/download-artifact@v3
+        uses: actions/download-artifact@v4
         with:
           name: star-sw-${{ env.STARENV }}
           path: /tmp