remove typo

Author: cvanelteren

.github/workflows/build.yml

@@ -75,7 +75,6 @@ jobs:
             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=/project/extern
           CIBW_TEST_COMMAND: >
             cd {project}
             pip install pytest