appveyor: Install astroid explicitly
appveyor: Install astroid explicitly

Workaround for https://github.com/coala-analyzer/coala/issues/879

tltuan/coala,tushar-rishav/coala,yashLadha/coala,Tanmay28/coala,yland/coala,sophiavanvalkenburg/coala,arjunsinghy96/coala,MariosPanag/coala,arafsheikh/coala,refeed/coala,ManjiriBirajdar/coala,shreyans800755/coala,dagdaggo/coala,FeodorFitsner/coala,meetmangukiya/coala,ayushin78/coala,andreimacavei/coala,MariosPanag/coala,aptrishu/coala,sagark123/coala,yland/coala,arush0311/coala,nemaniarjun/coala,yashtrivedi96/coala,Tanmay28/coala,Asalle/coala,swatilodha/coala,tltuan/coala,SambitAcharya/coala,mr-karan/coala,ayushin78/coala,sophiavanvalkenburg/coala,NalinG/coala,Uran198/coala,stevemontana1980/coala,Tanmay28/coala,svsn2117/coala,saurabhiiit/coala,scottbelden/coala,Nosferatul/coala,Uran198/coala,netman92/coala,rresol/coala,SambitAcharya/coala,impmihai/coala,SambitAcharya/coala,Uran198/coala,Balaji2198/coala,karansingh1559/coala,andreimacavei/coala,dagdaggo/coala,FeodorFitsner/coala,karansingh1559/coala,ManjiriBirajdar/coala,scottbelden/coala,refeed/coala,Tanmay28/coala,scriptnull/coala,vinc456/coala,NalinG/coala,SambitAcharya/coala,arjunsinghy96/coala,yland/coala,RJ722/coala,SambitAcharya/coala,kartikeys98/coala,AdeshAtole/coala,lonewolf07/coala,d6e/coala,damngamerz/coala,Shade5/coala,Nosferatul/coala,Asnelchristian/coala,incorrectusername/coala,aptrishu/coala,shreyans800755/coala,dagdaggo/coala,meetmangukiya/coala,SanketDG/coala,SambitAcharya/coala,kartikeys98/coala,coala-analyzer/coala,kartikeys98/coala,Tanmay28/coala,stevemontana1980/coala,rimacone/testing2,arafsheikh/coala,coala-analyzer/coala,SanketDG/coala,jayvdb/coala,mr-karan/coala,abhiroyg/coala,djkonro/coala,SambitAcharya/coala,svsn2117/coala,Tanmay28/coala,sophiavanvalkenburg/coala,incorrectusername/coala,Tanmay28/coala,NalinG/coala,Asalle/coala,rimacone/testing2,coala/coala,tltuan/coala,JohnS-01/coala,arush0311/coala,sudheesh001/coala,coala/coala,saurabhiiit/coala,sils1297/coala,yashtrivedi96/coala,swatilodha/coala,AbdealiJK/coala,scriptnull/coala,damngamerz/coala,sagark123/coala,rimacone/testing2,Balaji2198/coala,refeed/coala,ManjiriBirajdar/coala,mr-karan/coala,Shade5/coala,Balaji2198/coala,scottbelden/coala,svsn2117/coala,Nosferatul/coala,MattAllmendinger/coala,vinc456/coala,CruiseDevice/coala,MattAllmendinger/coala,impmihai/coala,RJ722/coala,aptrishu/coala,NiklasMM/coala,NalinG/coala,AdeshAtole/coala,NalinG/coala,scriptnull/coala,saurabhiiit/coala,Asnelchristian/coala,abhiroyg/coala,ayushin78/coala,NiklasMM/coala,abhiroyg/coala,JohnS-01/coala,arush0311/coala,AbdealiJK/coala,MattAllmendinger/coala,AdeshAtole/coala,yashtrivedi96/coala,sagark123/coala,MariosPanag/coala,CruiseDevice/coala,netman92/coala,coala-analyzer/coala,swatilodha/coala,NalinG/coala,arjunsinghy96/coala,impmihai/coala,sudheesh001/coala,d6e/coala,incorrectusername/coala,andreimacavei/coala,sils1297/coala,djkonro/coala,tushar-rishav/coala,nemaniarjun/coala,meetmangukiya/coala,NalinG/coala,netman92/coala,JohnS-01/coala,karansingh1559/coala,jayvdb/coala,arafsheikh/coala,scriptnull/coala,shreyans800755/coala,tushar-rishav/coala,FeodorFitsner/coala,Shade5/coala,scriptnull/coala,sils1297/coala,jayvdb/coala,nemaniarjun/coala,Asnelchristian/coala,damngamerz/coala,rresol/coala,AbdealiJK/coala,SanketDG/coala,RJ722/coala,scriptnull/coala,coala/coala,Tanmay28/coala,lonewolf07/coala,CruiseDevice/coala,yashLadha/coala,Asalle/coala,vinc456/coala,lonewolf07/coala,yashLadha/coala,stevemontana1980/coala,sudheesh001/coala,djkonro/coala,d6e/coala,scriptnull/coala,NiklasMM/coala,rresol/coala