Build(deps): Bump actions/upload-artifact from 5 to 6

Bumps [actions/upload-artifact](https://github.com/actions/upload-artifact) from 5 to 6.
- [Release notes](https://github.com/actions/upload-artifact/releases)
- [Commits](actions/upload-artifact@v5...v6)

---
updated-dependencies:
- dependency-name: actions/upload-artifact
  dependency-version: '6'
  dependency-type: direct:production
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <[email protected]>

Author: dependabot[bot]

.github/workflows/main.yml

@@ -133,7 +133,7 @@ jobs:
           ci/build-websocketpp.sh
       - name: upload VRPN logs
         if: failure() && startsWith(matrix.os, 'ubuntu')
-        uses: actions/upload-artifact@v5
+        uses: actions/upload-artifact@v6
         with:
           name: ${{ matrix.os }} ${{ matrix.xcode }}${{ env.CXX }} VRPN logs
           path: "vrpn/build/CMakeFiles/*.log"
@@ -176,7 +176,7 @@ jobs:
           ./configure --enable-gui --enable-ip-interface --enable-websocket-interface --enable-fudi-interface --enable-ecasound --enable-sofa --enable-polhemus --enable-razor --enable-vrpn --disable-browser-gui --enable-dynamic-asdf --disable-dependency-tracking
       - name: upload config.log
         if: failure()
-        uses: actions/upload-artifact@v5
+        uses: actions/upload-artifact@v6
         with:
           name: ${{ matrix.os }} ${{ matrix.xcode }}${{ env.CXX }} configure log
           path: config.log

.github/workflows/pd-externals.yml

@@ -34,7 +34,7 @@ jobs:
         run: |
           sh pd-lib-builder-iem-ci/localdeps/localdeps.linux.sh build/ssr_*.pd_linux
       - name: upload Linux externals
-        uses: actions/upload-artifact@v5
+        uses: actions/upload-artifact@v6
         with:
           name: linux-externals
           path: ssr/flext/build/*
@@ -72,7 +72,7 @@ jobs:
         run: |
           sh pd-lib-builder-iem-ci/localdeps/localdeps.macos.sh build/ssr_*.pd_darwin
       - name: upload macOS externals
-        uses: actions/upload-artifact@v5
+        uses: actions/upload-artifact@v6
         with:
           name: macos-externals
           path: ssr/flext/build/*
@@ -127,7 +127,7 @@ jobs:
         run: |
           sh pd-lib-builder-iem-ci/localdeps/localdeps.win.sh build/ssr_*.m_amd64
       - name: upload Windows externals
-        uses: actions/upload-artifact@v5
+        uses: actions/upload-artifact@v6
         with:
           name: windows-externals
           path: ssr/flext/build/*
@@ -168,7 +168,7 @@ jobs:
         run: |
           deken package -v $(git describe --tags --always) --objects flext/objects.txt ssr
       - name: Upload deken package
-        uses: actions/upload-artifact@v5
+        uses: actions/upload-artifact@v6
         with:
           name: Deken package
           path: "*.dek*"