add corrected path

Author: cvanelteren

.github/workflows/build.yml

@@ -74,9 +74,9 @@ jobs:
           CIBW_BEFORE_BUILD: >
             python -c "import utils; utils.GeosLibrary('${{ env.GEO_VERSION }}').build('extern', njobs=16)"
           CIBW_ENVIRONMENT: >
-            GEOS_DIR=${{ github.workspace }}${{ runner.os == 'Windows' && '\\extern' || '/extern' }}
-            CFLAGS=-I${{ github.workspace }}${{ runner.os == 'Windows' && '\\extern\\include' || '/extern/include' }}
-            LDFLAGS=-L${{ github.workspace }}${{ runner.os == 'Windows' && '\\extern\\lib' || '/extern/lib' }}
+            GEOS_DIR=${{ github.workspace }}${{ runner.os == 'Windows' && '\\project\\extern' || '/project/extern' }}
+            CFLAGS=-I${{ github.workspace }}${{ runner.os == 'Windows' && '\\project\\extern\\include' || '/project/extern/include' }}
+            LDFLAGS=-L${{ github.workspace }}${{ runner.os == 'Windows' && '\\project\\extern\\lib' || '/project/extern/lib' }}
 
           CIBW_TEST_COMMAND: >
             cd {project}