try changing TEMP dir on Windows to get shorter paths

Author: slayoo

.github/workflows/tests+artifacts+pypi.yml

@@ -48,6 +48,7 @@ jobs:
           echo CMAKE_ARGS="-DCMAKE_CXX_COMPILER=D:/a/_temp/msys64/mingw64/bin/g++.exe" >> $GITHUB_ENV
           echo CMAKE_ARGS="-DCMAKE_MAKE_PROGRAM=D:/a/_temp/msys64/mingw64/bin/ninja.exe" >> $GITHUB_ENV
           echo CMAKE_GENERATOR="Ninja" >> $GITHUB_ENV
+          echo TEMP="D:/a/_temp/" >> $GITHUB_ENV
 
       - uses: actions/checkout@v2
         with: