Upgrade the minimum python version to 3.6

CHANGELOG.md

@@ -4,6 +4,7 @@
 ### Added
 - The (1+z1)/(1+z2) factor between observed and grid flux densities caused by the differential redshifting is now taken into account. With a default grid redshift rounding of two decimals this yields a difference of at most 0.5% in the estimated physical properties at z=0 and even less at higher z. (Médéric Boquien)
 ### Changed
+- Python 3.6 is now the minimum required version. (Médéric Boquien)
 - The logo has now been moved to the lower-right corner of the figure so that it does not overlap with any information and it has been updated for a less pixelated version. (Médéric Boquien & Rodrigo González Castillo)
 - The wavelength range in SED plots is now dynamically adapted to cover the observed wavelengths. (Médéric Boquien)
 ### Fixed

pcigale/__init__.py

@@ -54,11 +54,8 @@ def run(config):
 
 
 def main():
-    if sys.version_info[:2] < (3, 5):
-        raise Exception("Python {}.{} is unsupported. Please upgrade to "
-                        "Python 3.5 or later.".format(*sys.version_info[:2]))
     if sys.version_info[:2] < (3, 6):
-        print("Python {}.{} detected. For better performance we recommend "
+        raise Exception("Python {}.{} is unsupported. Please upgrade to "
                         "Python 3.6 or later.".format(*sys.version_info[:2]))
 
     # We set the sub processes start method to spawn because it solves