Modernize usage of Vcpkg in CI

Use Vcpkg's manifest mode.

.github/workflows/cmake.yml

@@ -51,18 +51,14 @@ jobs:
       run: |
         echo "local_app_data=$LOCALAPPDATA" >> $GITHUB_ENV
         echo "vcpkg_root=$VCPKG_INSTALLATION_ROOT" >> $GITHUB_ENV
-        vcpkg search icu | awk '$1=="icu"{ print "icu_ver="$2 }' >> $GITHUB_ENV
 
     - uses: actions/cache@v3
       with:
         # use backslashes in path here for Windows.
         path: ${{ env.local_app_data }}\vcpkg\archives
-        key: windows-vcpkg-cache-${{ env.icu_ver }}
+        key: windows-vcpkg-cache-${{ hashFiles('vcpkg.json') }}
         restore-keys: windows-vcpkg-cache-
 
-    - name: Pull Vcpkg dependencies
-      run: vcpkg install icu getopt --triplet=x64-windows
-
     - name: Configure CMake
       run: cmake -B ${{github.workspace}}/build -DCMAKE_BUILD_TYPE=${{env.BUILD_TYPE}}
       env:

README.md

@@ -102,9 +102,9 @@ manuals.
 1.  Install Visual Studio 2017 or newer. Alternatively, you can use
     Visual Studio Build Tools.
 2.  Install Git for Windows and Cmake.
-3.  Install vcpkg in some folder, e.g. in `c:\vcpkg`.
-4.  Run `vcpkg install icu getopt --triplet=x64-windows`.
-5.  Run the commands bellow.
+3.  Install Vcpkg in some folder, e.g. in `c:\vcpkg`.
+4.  Run the commands bellow. Vcpkg will work in manifest mode and it will
+    automatically install the dependencies.
 
 <!-- end list -->
 

vcpkg.json

@@ -0,0 +1,17 @@
+{
+  "builtin-baseline": "2f9972005f61f02fa3cda7fc062d1b834b534b8d",
+  "dependencies": [
+    {
+      "name": "catch2",
+      "version>=": "2.13.9"
+    },
+    {
+      "name": "getopt",
+      "version>=": "0#2"
+    },
+    {
+      "name": "icu",
+      "version>=": "69.1#18"
+    }
+  ]
+}