Update main.yml to use actions/cache@4 (@1 deprecated)

This needs to be tested.

Author: bmunkholm

.github/workflows/build.yml

@@ -36,15 +36,15 @@ jobs:
           submodules: true
 
       - name: NuGet Cache
-        uses: actions/cache@v1
+        uses: actions/cache@v4
         with:
           path: ~/.nuget/packages
           key: ${{ runner.os }}-nuget-${{ hashFiles('**/Directory.Build.targets') }}
           restore-keys: |
             ${{ runner.os }}-nuget-
 
       - name: cr8 Cache
-        uses: actions/cache@v1
+        uses: actions/cache@v4
         with:
           path: ~/.cache/cr8/crates
           key: cr8-4.2.x