Remove py38 reference

Signed-off-by: Eric Kerfoot <eric.kerfoot@kcl.ac.uk>

Author: ericspod

pyproject.toml

@@ -9,7 +9,7 @@ requires = [
 
 [tool.black]
 line-length = 120
-target-version = ['py38', 'py39', 'py310', 'py311', 'py312']
+target-version = ['py39', 'py310', 'py311', 'py312']
 include = '\.pyi?$'
 exclude = '''
 (