Bump action scripts used to version 4.

This tries to fix the build error showing up at the GitHub CI Windows
build.

The build reports an unsupported node version that is used in one of the
"official" action scripts (in that case checkout@v3). Therefore the
build now uses version 4 on all scripts.

.github/workflows/cmake-win.yml

@@ -15,7 +15,7 @@ jobs:
     timeout-minutes: 30
 
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4
         with:
           fetch-tags: true
       - uses: microsoft/[email protected]
@@ -81,7 +81,7 @@ jobs:
           echo "Listing install dir: ${{ github.workspace }}\dcmtk-${{ env.NOW }}-${{ env.COMMIT_SHORT_SHA }}"
           ls ${{ github.workspace }}\dcmtk-${{ env.NOW }}-${{ env.COMMIT_SHORT_SHA }}
 
-      - uses: actions/upload-artifact@v3
+      - uses: actions/upload-artifact@v4
         with:
             name: dcmtk-install-zip-package
             path: ${{ github.workspace }}\dcmtk-${{ env.NOW }}-${{ env.COMMIT_SHORT_SHA }}\dcmtk-*-win64.zip
@@ -98,10 +98,10 @@ jobs:
     needs: build-windows
 
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4
         with:
           fetch-tags: true
-      - uses: actions/download-artifact@v3
+      - uses: actions/download-artifact@v4
         with:
           name: dcmtk-install-zip-package
           path: ${{ github.workspace }}\dcmtk-install