ci: use jurplel/install-qt-action@v4 and fix caching

Author: pbek

.github/workflows/build.yml

@@ -52,50 +52,44 @@ jobs:
       # Install Qt
       #
 
-    - name: Cache Qt
-      id: cache-qt
-      uses: actions/cache@v3
-      with:
-        path: ../Qt
-        key: ${{ runner.os }}-QtCache-${{ matrix.qt-version }}
     # https://github.com/marketplace/actions/install-qt
     - if: contains( matrix.os, 'windows') && ( matrix.qt-version == '5.7' )
       name: Install Qt 5.7 on Windows
-      uses: jurplel/install-qt-action@v2
+      uses: jurplel/install-qt-action@v4
       with:
         version: ${{ matrix.qt-version }}
         arch: win32_mingw53
         # try mirror
 #        mirror: 'http://mirrors.ocf.berkeley.edu/qt/'
-        cached: ${{ steps.cache-qt.outputs.cache-hit }}
+        cache: true
         aqtversion: '==0.9.4'
 #        py7zrversion: '==0.9.0'
     - if: contains( matrix.os, 'windows') && ( matrix.qt-version == '5.15.2' )
       name: Install Qt 5.15.2 on Windows
-      uses: jurplel/install-qt-action@v2
+      uses: jurplel/install-qt-action@v4
       with:
         version: ${{ matrix.qt-version }}
         arch: win64_mingw81
-        cached: ${{ steps.cache-qt.outputs.cache-hit }}
+        cache: true
     - if: contains( matrix.os, 'windows') && ( matrix.qt-version != '5.7' ) && ( matrix.qt-version != '5.15.2' )
       name: Install Qt on Windows
-      uses: jurplel/install-qt-action@v2
+      uses: jurplel/install-qt-action@v4
       with:
         version: ${{ matrix.qt-version }}
         arch: win64_mingw73
-        cached: ${{ steps.cache-qt.outputs.cache-hit }}
+        cache: true
     - if: false == contains( matrix.os, 'windows') && !startsWith( matrix.qt-version, '6.' )
       name: Install Qt
-      uses: jurplel/install-qt-action@v2
+      uses: jurplel/install-qt-action@v4
       with:
         version: ${{ matrix.qt-version }}
-        cached: ${{ steps.cache-qt.outputs.cache-hit }}
+        cache: true
     - if: false == contains( matrix.os, 'windows') && startsWith( matrix.qt-version, '6.' )
       name: Install Qt
-      uses: jurplel/install-qt-action@v2
+      uses: jurplel/install-qt-action@v4
       with:
         version: ${{ matrix.qt-version }}
-        cached: ${{ steps.cache-qt.outputs.cache-hit }}
+        cache: true
 
       #
       # Build qmarkdowntextedit