CI : Update to node20 actions

.github/workflows/main.yml

@@ -79,16 +79,12 @@ jobs:
       ARNOLD_FORCE_ABORT_ON_LICENSE_FAIL: 0 # And don't abort because the license isn't found
       GAFFER_BUILD_DIR: "./build"
       GAFFER_CACHE_DIR: "./sconsCache"
-      # GitHub have moved to running actions on Node20, which prevents them from
-      # running on CentOS 7. The below allows actions to continue running on Node16
-      # until October.
-      ACTIONS_ALLOW_USE_UNSECURE_NODE_VERSION: true
 
     steps:
 
-    - uses: actions/checkout@v3
+    - uses: actions/checkout@v4
 
-    - uses: ilammy/msvc-dev-cmd@v1.12.1
+    - uses: ilammy/msvc-dev-cmd@v1.13.0
       with:
         sdk: 10.0.17763.0
 
@@ -158,7 +154,7 @@ jobs:
       if: runner.os == 'Windows'
 
     - name: Cache
-      uses: actions/cache@v3
+      uses: actions/cache@v4
       with:
         path: ${{ env.GAFFER_CACHE_DIR }}
         key: ${{ runner.os }}-${{ matrix.containerImage }}-${{env.GAFFER_DEPENDENCIES_HASH}}-${{ matrix.buildType }}-${{ github.sha }}
@@ -245,10 +241,13 @@ jobs:
         echo "::remove-matcher owner=validateRelease::"
       if: matrix.publish
 
-    - uses: actions/upload-artifact@v3
+    - uses: actions/upload-artifact@v4
       with:
         name: ${{ env.GAFFER_BUILD_NAME }}
         path: ${{ env.GAFFER_BUILD_NAME }}.${{ env.PACKAGE_EXTENSION }}
+        # Using compression-level 0 avoids compressing our already compressed
+        # package and results in a significantly faster upload.
+        compression-level: 0
       if: matrix.publish
 
     - name: Publish Release