CI: work around vcpkg openssl issue with OpenSSL providers

Currently, the openssl package from vcpkg uses an incorrect, hard-coded
default location for OpenSSL providers under C:\vcpkg\packages, which
is supposed to be a temporary directory.

Override it with the OPENSSL_MODULES environment variable as a
temporary workaround.

.github/workflows/windows.yml

@@ -44,6 +44,10 @@ jobs:
       GITPULLOPTIONS: --no-tags origin ${{github.ref}}
       PATCH: C:\msys64\usr\bin\patch.exe
       OS_VER: windows-${{ matrix.vs < 2022 && '2019' || matrix.vs }}
+      # FIXME: This is a workaround for the vcpkg's issue present as of openssl 3.1.1
+      # where OpenSSL's default modules directory is incorrectly set to C:\vcpkg\packages\openssl_x64-windows\bin
+      # cf. https://github.com/ruby/openssl/pull/635#issuecomment-1596833720
+      OPENSSL_MODULES: C:\vcpkg\installed\x64-windows\bin
     steps:
       - run: md build
         working-directory: