Updated the X11 release to Ubuntu 22.04 + Qt 5.15.12

.github/workflows/x11.yml

@@ -4,18 +4,20 @@ on: [push, pull_request, workflow_dispatch]
 env:
   TOOLS_URL: https://github.com/mmatyas/pegasus-frontend/releases/download/alpha1
   QT_TARGET: x11-static
-  QT_VERSION: qt51510
-  QT_VERSION_PRETTY: "5.15.10"
+  QT_VERSION: qt51512
+  QT_VERSION_PRETTY: "5.15.12"
   SDL_TARGET: x11-bionic
   SDL_VERSION: "2.0.20"
 
 
 jobs:
   x11:
-    runs-on: ubuntu-20.04
     strategy:
       matrix:
         buildgen: [cmake, qmake, qmake-lcov]
+        runner: ['ubuntu-22.04']
+
+    runs-on: matrix.runner
     steps:
       - uses: actions/checkout@v3
         with: {submodules: 'recursive', fetch-depth: 0, fetch-tags: true}
@@ -29,12 +31,10 @@ jobs:
             ccache-x11-
             ccache-
 
-      - name: GCC PPA
-        run: sudo add-apt-repository ppa:ubuntu-toolchain-r/test
       - name: APT deps
         run: sudo apt-get update && sudo apt-get install -y
           ccache
-          g++-10
+          g++
           lcov
           libasound-dev
           libgl1-mesa-dev
@@ -74,9 +74,6 @@ jobs:
 
       - name: Configure (cmake)
         if: matrix.buildgen == 'cmake'
-        env:
-          CC: gcc-10
-          CXX: g++-10
         run: cmake
           -B build
           -G Ninja