fix(ci): Use xvfb-run

Author: ids1024

.github/workflows/ci.yml

@@ -12,9 +12,9 @@ jobs:
   run-tests:
     runs-on: ubuntu-latest
     steps:
-    - run: sudo apt-get install cargo libgtk-3-dev libhidapi-dev libusb-1.0-0-dev
+    - run: sudo apt-get install cargo libgtk-3-dev libhidapi-dev libusb-1.0-0-dev xvfb
     - uses: actions/checkout@v2
-    - run: cargo test
+    - run: xvfb-run cargo test
 
   linux-x86_64:
     runs-on: ubuntu-latest
@@ -32,11 +32,12 @@ jobs:
     runs-on: ubuntu-latest
     needs: linux-x86_64
     steps:
+    - run: sudo apt-get install xvfb
     - uses: actions/download-artifact@v2
       with:
         name: keyboard-configurator-linux-x86_64-${{ github.sha }}
     - run: chmod +x keyboard-configurator-x86_64.AppImage
-    - run: ./keyboard-configurator-x86_64.AppImage --help-gtk
+    - run: xvfb-run ./keyboard-configurator-x86_64.AppImage --help-gtk
 
   windows-mingw32:
     runs-on: windows-latest