Simplify windows job a little by removing absolute paths

.github/workflows/ci-main.yml

@@ -275,29 +275,25 @@ jobs:
     runs-on: windows-2019
 
     steps:
-      - uses: actions/checkout@v3
-        with:
-          submodules: "recursive"
+      - { uses: actions/checkout@v3, with: { submodules: "recursive" } }
 
       - name: Cache object files
         id: windows-cache
         uses: actions/cache@v3
         with:
-          path: |
-            D:/a/wesnoth/wesnoth/vcpkg_installed
+          path: vcpkg_installed  # vcpkg generates this dir next to vcpkg.json
           key: win-cache-master-${{ matrix.cfg }}-0002
 
       - name: Add msbuild to PATH
         uses: microsoft/setup-msbuild@v1.1.3
 
-# checkout a specific commit to prevent cmake from thinking it can't use the cached dependencies anymore
+# checkout a specific commit to prevent vcpkg ABI changes from invalidating the cache (https://learn.microsoft.com/en-us/vcpkg/users/binarycaching#abi-hash)
 # the commit itself is just whatever happens to be the latest commit when a newer version is needed
       - name: Build vcpkg
         run: |
-          git clone https://github.com/microsoft/vcpkg.git D:/a/wesnoth/vcpkg
-          cd D:/a/wesnoth/vcpkg
-          git checkout 5b081066f0740e54bdcbe4d0772d85dbb1d8e266
-          D:/a/wesnoth/vcpkg/bootstrap-vcpkg.bat
+          git clone https://github.com/microsoft/vcpkg
+          git -C vcpkg checkout 5b081066f0740e54bdcbe4d0772d85dbb1d8e266
+          vcpkg/bootstrap-vcpkg.bat
 
       - name: Setup cmake
         uses: jwlawson/actions-setup-cmake@v1.13
@@ -306,19 +302,19 @@ jobs:
 
       - name: Run cmake
         run: |
-          cmake -DCMAKE_BUILD_TYPE=%CFG% -DENABLE_GAME=true -DENABLE_SERVER=true -DENABLE_CAMPAIGN_SERVER=true -DENABLE_TESTS=true -DENABLE_MYSQL=false -DENABLE_NLS=false -DVCPKG_TARGET_TRIPLET=x64-windows -DCMAKE_TOOLCHAIN_FILE=D:/a/wesnoth/vcpkg/scripts/buildsystems/vcpkg.cmake -DCMAKE_GENERATOR_PLATFORM=x64 -G "Visual Studio 16 2019" .
+          cmake -DCMAKE_BUILD_TYPE=%CFG% -DENABLE_GAME=true -DENABLE_SERVER=true -DENABLE_CAMPAIGN_SERVER=true -DENABLE_TESTS=true -DENABLE_MYSQL=false -DENABLE_NLS=false -DVCPKG_TARGET_TRIPLET=x64-windows -DCMAKE_TOOLCHAIN_FILE=vcpkg/scripts/buildsystems/vcpkg.cmake -DCMAKE_GENERATOR_PLATFORM=x64 -G "Visual Studio 16 2019" .
 
 # delete buildtrees directory to free up space after cmake invokes vcpkg to build the dependencies
 # otherwise the job was failing when trying to write a .obj file
 # building vcpkg on the more spacious C drive didn't work since for some reason vcpkg decides to not create the pango/cairo pkgconfig files there
       - name: Build wesnoth, wesnothd, campaignd and unit tests
         run: |
-          rmdir /s /q D:\a\wesnoth\vcpkg\buildtrees
+          rmdir /s /q vcpkg\buildtrees
           MSBuild.exe wesnoth.sln -p:Configuration=%CFG%
 
       - name: Run WML unit tests
         if: matrix.cfg == 'Release'
-        run: python run_wml_tests -v -g -c -t 20 -p D:/a/wesnoth/wesnoth/%CFG%/wesnoth.exe
+        run: python run_wml_tests -v -g -c -t 20 -p %CFG%/wesnoth.exe
 
 # run after all other jobs have completed to check overall build status
   discord-notification: