Update github actions upload artifact to v4

This is part of #3050, but thinking about this logically, the deprecation of v3 happens in just 3 days, so unless we want to have .NET 9 testing done in the next 3 days (unlikely?), it's not a great idea to let this break.

Author: hakusaro

.github/workflows/ci-otapi3.yml

@@ -63,14 +63,14 @@ jobs:
             tar -cvf ../../../../../../TShock-Beta-${{ matrix.arch }}-Release.tar *
 
       - name: Upload artifact (non-Windows)
-        uses: actions/upload-artifact@v3
+        uses: actions/upload-artifact@v4
         if: ${{ matrix.arch != 'win-x64' }}
         with:
           name: TShock-Beta-${{ matrix.arch }}-Release
           path: TShock-Beta-${{ matrix.arch }}-Release.tar
 
       - name: Upload artifact (Windows)
-        uses: actions/upload-artifact@v3
+        uses: actions/upload-artifact@v4
         if: ${{ matrix.arch == 'win-x64' }}
         with:
           name: TShock-Beta-${{ matrix.arch }}-Release