Add optional dependencies to windows and macos targets in build-tests.yml (#229)

Install and validate integration with as many optional dependencies on all testing platforms when doing CI build tests.

- For windows-latest, use vcpkg to install zlib, libqrencode, and zint.
- For macos-latest, use brew to install zlib, qrencode, and zint.
- Made zint version detection more robust across platforms.

.github/workflows/build-tests.yml

@@ -6,16 +6,12 @@
 #     - windows-latest - cl
 #     - macos-latest   - clang
 #
-# TODO:
-#     - install optional dependencies for windows-latest and macos-latest
       
 
 name: Multi-Platform Build Tests
 
 on:
   push:
-  pull_request:
-    branches: [ master ]
 
 jobs:
   build:
@@ -66,24 +62,50 @@ jobs:
         # install zint-2.15.0 from source
         wget https://downloads.sourceforge.net/project/zint/zint/2.15.0/zint-2.15.0-src.tar.gz && tar xzf zint-2.15.0-src.tar.gz && ( cd zint-2.15.0-src && mkdir build && cd build && cmake .. && make && sudo make install )
 
+    - name: Pre-install vcpkg (Windows)
+      if: startsWith( matrix.os, 'windows-' )
+      shell: bash
+      run: |
+        git clone --depth 1 https://github.com/microsoft/vcpkg.git
+
+    - name: Restore vcpkg cache (Windows)
+      if: startsWith(matrix.os, 'windows-')
+      uses: actions/cache@v4
+      with:
+        path: |
+          ${{ github.workspace }}/vcpkg/installed
+          ${{ github.workspace }}/vcpkg/downloads
+        key: vcpkg-${{ runner.os }}-${{ hashFiles('.github/workflows/build-tests.yml') }}
+        restore-keys: |
+          vcpkg-${{ runner.os }}-
+
     - name: Install optional dependencies (Windows)
       if: startsWith( matrix.os, 'windows-' )
       shell: bash
       run: |
         # install packages
+        ./vcpkg/bootstrap-vcpkg.sh
+        ./vcpkg/vcpkg install pkgconf
+        ./vcpkg/vcpkg install zlib
+        ./vcpkg/vcpkg install libqrencode
+        ./vcpkg/vcpkg install zint
+        echo "TOOLCHAIN_FILE=${{ github.workspace }}/vcpkg/scripts/buildsystems/vcpkg.cmake" >> $GITHUB_ENV
 
     - name: Install optional dependencies (MacOS)
       if: startsWith( matrix.os, 'macos-' )
       shell: bash
       run: |
         # install packages
+        brew install zlib
+        brew install qrencode
+        brew install zint
 
     - name: Install Qt
       uses: jurplel/install-qt-action@v4
       with:
         version: '6.2.*'
         install-deps: 'true'
-        archives: 'qtbase qtsvg qttools icu'
+        archives: 'qtbase qtsvg qttools icu qttranslations'
 
     - name: Set reusable strings
       id: strings
@@ -97,6 +119,7 @@ jobs:
         -DCMAKE_CXX_COMPILER=${{ matrix.cpp_compiler }}
         -DCMAKE_C_COMPILER=${{ matrix.c_compiler }}
         -DCMAKE_BUILD_TYPE=${{ matrix.build_type }}
+        -DCMAKE_TOOLCHAIN_FILE=${{ env.TOOLCHAIN_FILE }}
         -S ${{ github.workspace }}
 
     - name: Build