Github Actions: use Qt 5.11.0 on windows.

qt < 5.11 has a bug in qCountLeadingZeroBits function (QtCore/qalgorithms.h).
This function is marked constexpr but returns a non-const value.

MSVC compilers will pick this up as an C3615 error.
See https://docs.microsoft.com/en-us/cpp/error-messages/compiler-errors-2/compiler-error-c3615

.github/workflows/ci.yml

@@ -47,7 +47,7 @@ jobs:
       if: startsWith(matrix.build, 'gui') && runner.os != 'Linux'
       uses: jurplel/install-qt-action@v2
       with:
-        version: '5.9'
+        version: '5.11.0'
 
     - name: Configure
       shell: bash

.github/workflows/package.yml

@@ -63,7 +63,7 @@ jobs:
         uses: jurplel/install-qt-action@v2
         with:
           arch: ${{ matrix.qt-arch }}
-          version: '5.9'
+          version: '5.11.0'
 
       - name: Configure
         run: cmake -A ${{matrix.arch}} -DCOMPONENT_GUI=ON -DCOMPONENT_CLI=ON -D CMAKE_BUILD_TYPE=Release -D CPACK_GENERATOR=NSIS -S . -B build