CI: Set PROJ_DATA env var so proj finds proj.db on Windows

Author: joto

.github/actions/win-test/action.yml

@@ -8,6 +8,7 @@ runs:
       run: ctest --output-on-failure -C Release
       env:
         PYTHONUTF8: 1
+        PROJ_DATA: c:/vcpkg/installed/x64-windows/share/proj/ # so proj finds proj.db
       shell: bash
       working-directory: build