Fix WIN_INSTALL_DIR path conversion command

Author: philbrks

.github/workflows/win-build.yml

@@ -141,7 +141,7 @@ jobs:
           touch "${HOME}/forWinDialog-5.12.7"
           mkdir "${HOME}/install_dir"
           echo INSTALL_DIR=${HOME}/install_dir >> $GITHUB_ENV
-          echo "WIN_INSTALL_DIR=`cygpath -w -f ${HOME}/install_dir`" >> $GITHUB_ENV
+          echo "WIN_INSTALL_DIR=`cygpath -w ${HOME}/install_dir`" >> $GITHUB_ENV
         working-directory: generic
       - name: Configure and Build Tcl (${{ matrix.config }})
         run: |