ci(dependabot): bump aganders3/headless-gui from 1 to 2

Bumps [aganders3/headless-gui](https://github.com/aganders3/headless-gui) from 1 to 2.
- [Release notes](https://github.com/aganders3/headless-gui/releases)
- [Commits](aganders3/headless-gui@v1...v2)

---
updated-dependencies:
- dependency-name: aganders3/headless-gui
  dependency-type: direct:production
  update-type: version-update:semver-major
...

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

.github/workflows/test_conversion.yml

@@ -61,7 +61,7 @@ jobs:
 
       - name: Test Conversion
         id: test-without-napari
-        uses: aganders3/headless-gui@v1
+        uses: aganders3/headless-gui@v2
         continue-on-error: true
         with:
           run: npe2 convert ./plugin_repo
@@ -73,13 +73,13 @@ jobs:
       - name: Test Conversion again with napari
         id: test-with-napari
         if: ${{ steps.test-without-napari.outcome == 'failure' }}
-        uses: aganders3/headless-gui@v1
+        uses: aganders3/headless-gui@v2
         with:
           run: npe2 convert ./plugin_repo
 
       - name: Test Conversion again with napari
         if: ${{ steps.test-without-napari.outcome == 'failure' && steps.test-with-napari.outcome == 'failure' }}
-        uses: aganders3/headless-gui@v1
+        uses: aganders3/headless-gui@v2
         with:
           # try without modifying directory
           run: npe2 convert -n ${{ matrix.plugin }}