Bump actions/upload-artifact from 6 to 7 (#2017)

Bumps [actions/upload-artifact](https://github.com/actions/upload-artifact) from 6 to 7.
- [Release notes](https://github.com/actions/upload-artifact/releases)
- [Commits](actions/upload-artifact@v6...v7)

---
updated-dependencies:
- dependency-name: actions/upload-artifact
  dependency-version: '7'
  dependency-type: direct:production
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Author: dependabot[bot]

.github/workflows/build.yml

@@ -74,7 +74,7 @@ jobs:
       working-directory: ${{env.BUILD_DIR}}
       run: make releasezip
     - name: Upload Installer
-      uses: actions/upload-artifact@v6
+      uses: actions/upload-artifact@v7
       with:
         name: Pinta-linux-dotnet-${{matrix.dotnet_version}}.zip
         path: ${{env.BUILD_DIR}}/pinta-${{env.PINTA_VERSION}}.zip
@@ -126,7 +126,7 @@ jobs:
 
     - name: Upload Installer
       if: github.event_name != 'pull_request'
-      uses: actions/upload-artifact@v6
+      uses: actions/upload-artifact@v7
       with:
         name: "Pinta-${{matrix.build.dotnet_rid}}.dmg"
         path: installer/macos/Pinta.dmg
@@ -176,7 +176,7 @@ jobs:
 
     - name: Upload Installer
       id: upload-unsigned-installer
-      uses: actions/upload-artifact@v6
+      uses: actions/upload-artifact@v7
       with:
         name: "Pinta-${{matrix.build.dotnet_rid}}.exe"
         path: installer/windows/Pinta.exe
@@ -199,7 +199,7 @@ jobs:
     - name: Upload Signed Installer
       if: startsWith( github.ref, 'refs/tags/' )
       id: upload-signed-installer
-      uses: actions/upload-artifact@v6
+      uses: actions/upload-artifact@v7
       with:
         name: "Pinta-signed-${{matrix.build.dotnet_rid}}.exe"
         path: ./signed-artifacts/Pinta.exe