CI: add jdcal to 3.6 build as openpyxl >= 2.4.5 is broken
CI: add jdcal to 3.6 build as openpyxl >= 2.4.5 is broken

datapythonista/pandas,MJuddBooth/pandas,MJuddBooth/pandas,DGrady/pandas,gfyoung/pandas,rs2/pandas,jmmease/pandas,amolkahat/pandas,linebp/pandas,GuessWhoSamFoo/pandas,jreback/pandas,harisbal/pandas,pandas-dev/pandas,jmmease/pandas,linebp/pandas,DGrady/pandas,nmartensen/pandas,nmartensen/pandas,Winand/pandas,harisbal/pandas,toobaz/pandas,winklerand/pandas,jreback/pandas,GuessWhoSamFoo/pandas,cython-testbed/pandas,TomAugspurger/pandas,jreback/pandas,Winand/pandas,Winand/pandas,DGrady/pandas,cbertinato/pandas,louispotok/pandas,cbertinato/pandas,datapythonista/pandas,gfyoung/pandas,jorisvandenbossche/pandas,linebp/pandas,jmmease/pandas,dsm054/pandas,jorisvandenbossche/pandas,TomAugspurger/pandas,jorisvandenbossche/pandas,zfrenchee/pandas,jmmease/pandas,cython-testbed/pandas,DGrady/pandas,Winand/pandas,pandas-dev/pandas,GuessWhoSamFoo/pandas,kdebrab/pandas,toobaz/pandas,zfrenchee/pandas,DGrady/pandas,Winand/pandas,jreback/pandas,nmartensen/pandas,winklerand/pandas,pandas-dev/pandas,DGrady/pandas,dsm054/pandas,louispotok/pandas,harisbal/pandas,Winand/pandas,datapythonista/pandas,amolkahat/pandas,gfyoung/pandas,louispotok/pandas,winklerand/pandas,dsm054/pandas,kdebrab/pandas,rs2/pandas,rs2/pandas,linebp/pandas,jreback/pandas,cython-testbed/pandas,nmartensen/pandas,MJuddBooth/pandas,cbertinato/pandas,linebp/pandas,datapythonista/pandas,MJuddBooth/pandas,cbertinato/pandas,louispotok/pandas,nmartensen/pandas,harisbal/pandas,zfrenchee/pandas,kdebrab/pandas,TomAugspurger/pandas,pratapvardhan/pandas,kdebrab/pandas,pratapvardhan/pandas,zfrenchee/pandas,pratapvardhan/pandas,gfyoung/pandas,amolkahat/pandas,GuessWhoSamFoo/pandas,dsm054/pandas,jmmease/pandas,TomAugspurger/pandas,GuessWhoSamFoo/pandas,amolkahat/pandas,zfrenchee/pandas,cython-testbed/pandas,jmmease/pandas,pratapvardhan/pandas,gfyoung/pandas,amolkahat/pandas,toobaz/pandas,toobaz/pandas,cython-testbed/pandas,rs2/pandas,winklerand/pandas,jorisvandenbossche/pandas,kdebrab/pandas,winklerand/pandas,nmartensen/pandas,pratapvardhan/pandas,pandas-dev/pandas,louispotok/pandas,linebp/pandas,MJuddBooth/pandas,dsm054/pandas,harisbal/pandas,cbertinato/pandas,toobaz/pandas,winklerand/pandas