doc: fix flake8 in generate changelog script
doc: fix flake8 in generate changelog script

kYc0o/RIOT,lazytech-org/RIOT,yogo1212/RIOT,gebart/RIOT,OlegHahm/RIOT,rfuentess/RIOT,neiljay/RIOT,kaspar030/RIOT,A-Paul/RIOT,josephnoir/RIOT,OTAkeys/RIOT,RIOT-OS/RIOT,jasonatran/RIOT,josephnoir/RIOT,kaspar030/RIOT,authmillenon/RIOT,mfrey/RIOT,jasonatran/RIOT,OlegHahm/RIOT,BytesGalore/RIOT,yogo1212/RIOT,josephnoir/RIOT,mtausig/RIOT,biboc/RIOT,kbumsik/RIOT,kbumsik/RIOT,OTAkeys/RIOT,miri64/RIOT,avmelnikoff/RIOT,x3ro/RIOT,kYc0o/RIOT,avmelnikoff/RIOT,mfrey/RIOT,authmillenon/RIOT,RIOT-OS/RIOT,cladmi/RIOT,lazytech-org/RIOT,x3ro/RIOT,avmelnikoff/RIOT,kbumsik/RIOT,rfuentess/RIOT,toonst/RIOT,RIOT-OS/RIOT,A-Paul/RIOT,neiljay/RIOT,yogo1212/RIOT,kYc0o/RIOT,aeneby/RIOT,basilfx/RIOT,authmillenon/RIOT,OTAkeys/RIOT,lazytech-org/RIOT,lazytech-org/RIOT,BytesGalore/RIOT,miri64/RIOT,BytesGalore/RIOT,aeneby/RIOT,x3ro/RIOT,mtausig/RIOT,A-Paul/RIOT,gebart/RIOT,kYc0o/RIOT,x3ro/RIOT,basilfx/RIOT,yogo1212/RIOT,rfuentess/RIOT,basilfx/RIOT,kaspar030/RIOT,authmillenon/RIOT,OlegHahm/RIOT,kaspar030/RIOT,kaspar030/RIOT,biboc/RIOT,OTAkeys/RIOT,kbumsik/RIOT,miri64/RIOT,basilfx/RIOT,toonst/RIOT,aeneby/RIOT,gebart/RIOT,OlegHahm/RIOT,aeneby/RIOT,mtausig/RIOT,neiljay/RIOT,yogo1212/RIOT,josephnoir/RIOT,RIOT-OS/RIOT,neiljay/RIOT,smlng/RIOT,kbumsik/RIOT,rfuentess/RIOT,miri64/RIOT,jasonatran/RIOT,miri64/RIOT,ant9000/RIOT,mfrey/RIOT,ant9000/RIOT,gebart/RIOT,BytesGalore/RIOT,basilfx/RIOT,biboc/RIOT,neiljay/RIOT,jasonatran/RIOT,toonst/RIOT,mtausig/RIOT,toonst/RIOT,OTAkeys/RIOT,ant9000/RIOT,cladmi/RIOT,josephnoir/RIOT,smlng/RIOT,aeneby/RIOT,ant9000/RIOT,mfrey/RIOT,cladmi/RIOT,smlng/RIOT,cladmi/RIOT,gebart/RIOT,RIOT-OS/RIOT,ant9000/RIOT,mtausig/RIOT,authmillenon/RIOT,OlegHahm/RIOT,cladmi/RIOT,mfrey/RIOT,smlng/RIOT,A-Paul/RIOT,authmillenon/RIOT,smlng/RIOT,yogo1212/RIOT,lazytech-org/RIOT,A-Paul/RIOT,avmelnikoff/RIOT,x3ro/RIOT,BytesGalore/RIOT,avmelnikoff/RIOT,biboc/RIOT,toonst/RIOT,jasonatran/RIOT,kYc0o/RIOT,biboc/RIOT,rfuentess/RIOT