Restore/save build outputs for incremental build

.github/workflows/build.yml

@@ -45,13 +45,27 @@ jobs:
         path: vcpkg_installed
         key: ${{ runner.os }}-${{ matrix.platform }}-${{ hashFiles('vcpkg.json') }}
 
+    - name: Restore incremental build cache
+      uses: actions/cache/restore@v4
+      if: github.ref != format('refs/heads/{0}', github.event.repository.default_branch)
+      with:
+        path: .build
+        key: buildCache-${{ runner.os }}-${{ matrix.platform }}-${{ github.sha }}
+        restore-keys: buildCache-${{ runner.os }}-${{ matrix.platform }}-
+
     - name: Build
       # Add additional options to the MSBuild command line here (like platform or verbosity level).
       # See https://docs.microsoft.com/visualstudio/msbuild/msbuild-command-line-reference
       run: |
         vcpkg integrate install
         msbuild /maxCpuCount /warnAsError /property:RunCodeAnalysis=true /property:Configuration=${{env.BUILD_CONFIGURATION}} ${{env.SOLUTION_FILE_PATH}}
 
+    - name: Save incremental build cache
+      uses: actions/cache/save@v4
+      with:
+        path: .build
+        key: buildCache-${{ runner.os }}-${{ matrix.platform }}-${{ github.sha }}
+
     - name: Test
       working-directory: ./test/
       run: ../.build/${{env.BUILD_CONFIGURATION}}_${{env.PLATFORM}}_test/test.exe