MAINT: Fix E275 test failures

[itrharrison]

A change in flake8 seems to mean that there are now a few cases which fail on E275 (missing whitespace after keyword):

skypy/pipeline/tests/test_skypy.py:61:11: E275 missing whitespace after keyword
skypy/pipeline/tests/test_skypy.py:81:15: E275 missing whitespace after keyword
skypy/pipeline/tests/test_skypy.py:86:15: E275 missing whitespace after keyword
skypy/pipeline/tests/test_skypy.py:90:15: E275 missing whitespace after keyword
skypy/pipeline/tests/test_skypy.py:93:11: E275 missing whitespace after keyword
skypy/pipeline/tests/test_skypy.py:103:11: E275 missing whitespace after keyword
skypy/pipeline/tests/test_skypy.py:109:11: E275 missing whitespace after keyword
skypy/pipeline/scripts/skypy.py:51:11: E275 missing whitespace after keyword
skypy/utils/photometry.py:4:12: E275 missing whitespace after keyword

I will fix these now.