Fix broken cpp-build-windows workflow (apache#316)

Fixes apache#307

### Modifications

Use the `vcpkg_installed/<triplet>` directory as the `OPENSSL_ROOT_DIR`,
for debug build, add the `vcpkg_installed/<triplet>/debug` directory as
well.

Author: BewareMyPower

CMakeLists.txt

@@ -40,11 +40,14 @@ if (VCPKG_TRIPLET)
     message(STATUS "Use CMAKE_PREFIX_PATH: ${CMAKE_PREFIX_PATH}")
     set(PROTOC_PATH "${CMAKE_PREFIX_PATH}/tools/protobuf/protoc")
     message(STATUS "Use protoc: ${PROTOC_PATH}")
-    set(VCPKG_DEBUG_ROOT "${PROJECT_SOURCE_DIR}/vcpkg_installed/${VCPKG_TRIPLET}/debug")
+    set(VCPKG_ROOT "${PROJECT_SOURCE_DIR}/vcpkg_installed/${VCPKG_TRIPLET}")
+    set(VCPKG_DEBUG_ROOT "${VCPKG_ROOT}/debug")
     if (CMAKE_BUILD_TYPE STREQUAL "Debug")
         set(ZLIB_ROOT ${VCPKG_DEBUG_ROOT})
-        set(OPENSSL_ROOT_DIR ${VCPKG_DEBUG_ROOT})
+        set(OPENSSL_ROOT_DIR ${VCPKG_ROOT} ${VCPKG_DEBUG_ROOT})
         set(CMAKE_PREFIX_PATH ${VCPKG_DEBUG_ROOT} ${CMAKE_PREFIX_PATH})
+    else ()
+        set(OPENSSL_ROOT_DIR ${VCPKG_ROOT})
     endif ()
     if (VCPKG_TRIPLET MATCHES ".*-static")
         set(LINK_STATIC ON)