COMP: Limit CI tests to Qt5.15 pre-generated release files

Author: hjmjohnson

.github/workflows/build.yml

@@ -184,12 +184,12 @@ jobs:
       matrix:
        macos-version:  ['latest']
        python-version: ['3.9']
-       qt-version: ['5.9.*']
+       qt-version: ['5.15.*']
        configuration: ['release','debug']
        include:
          - macos-version: 'latest'
            python-version: '3.11'
-           qt-version: '5.12.*'
+           qt-version: '5.15.*'
            configuration: 'debug'
     runs-on: macos-${{ matrix.macos-version }}
     steps:
@@ -276,15 +276,15 @@ jobs:
       matrix:
        qt-arch: ['win64_mingw73']
        python-version: ['3.10']
-       qt-version: ['5.12.*']
+       qt-version: ['5.15.*']
        python-arch: ['x64']
        pythonqtall-config: ['']
 #       msvc-toolset: ['14.0']
        include:
          - qt-arch: 'win64_msvc2017_64'
            python-version: '3.6'
            python-arch: 'x64'
-           qt-version: '5.11.*'
+           qt-version: '5.15.*'
 #           msvc-toolset: '14.16'
 
          - qt-arch: 'win64_msvc2019_64'
@@ -296,7 +296,7 @@ jobs:
          - qt-arch: 'win32_mingw53'
            python-version: '3.6'
            python-arch: 'x86'
-           qt-version: '5.11.*'
+           qt-version: '5.15.*'
 
 #Either MSVC2015 is sick or Qt5.9 is buggy :(
 #Main problem is QBasicMutex with default ctor, that (by no means) is missing in dll-export of QtCore, but linker tries to find it