update: install x11 libs in build-test workflow

Author: froz42

.github/workflows/build-test.yml

@@ -37,6 +37,8 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v3
+      - name: install x11 libs
+        run: sudo apt-get install libx11-dev
       - name: Make lib
         run: make -C library
       - name: Upload libfuncheck.so