[AIRFLOW-1781] Make search case-insensitive in LDAP group
[AIRFLOW-1781] Make search case-insensitive in LDAP group

Closes #2750 from patsak/f/ldap_search

artwr/airflow,wolfier/incubator-airflow,jgao54/airflow,gtoonstra/airflow,danielvdende/incubator-airflow,wolfier/incubator-airflow,wolfier/incubator-airflow,bolkedebruin/airflow,sekikn/incubator-airflow,airbnb/airflow,lyft/incubator-airflow,cfei18/incubator-airflow,akosel/incubator-airflow,criccomini/airflow,owlabs/incubator-airflow,artwr/airflow,artwr/airflow,akosel/incubator-airflow,lyft/incubator-airflow,malmiron/incubator-airflow,akosel/incubator-airflow,sergiohgz/incubator-airflow,sekikn/incubator-airflow,malmiron/incubator-airflow,owlabs/incubator-airflow,DinoCow/airflow,cfei18/incubator-airflow,cfei18/incubator-airflow,edgarRd/incubator-airflow,Fokko/incubator-airflow,Fokko/incubator-airflow,yk5/incubator-airflow,edgarRd/incubator-airflow,RealImpactAnalytics/airflow,adamhaney/airflow,edgarRd/incubator-airflow,subodhchhabra/airflow,nathanielvarona/airflow,lyft/incubator-airflow,jgao54/airflow,fenglu-g/incubator-airflow,wileeam/airflow,RealImpactAnalytics/airflow,bolkedebruin/airflow,sekikn/incubator-airflow,sid88in/incubator-airflow,fenglu-g/incubator-airflow,nathanielvarona/airflow,r39132/airflow,criccomini/airflow,mistercrunch/airflow,dhuang/incubator-airflow,sid88in/incubator-airflow,spektom/incubator-airflow,gtoonstra/airflow,criccomini/airflow,mistercrunch/airflow,r39132/airflow,DinoCow/airflow,danielvdende/incubator-airflow,CloverHealth/airflow,RealImpactAnalytics/airflow,subodhchhabra/airflow,artwr/airflow,apache/incubator-airflow,danielvdende/incubator-airflow,apache/airflow,owlabs/incubator-airflow,gtoonstra/airflow,Acehaidrey/incubator-airflow,CloverHealth/airflow,jgao54/airflow,mtagle/airflow,owlabs/incubator-airflow,Acehaidrey/incubator-airflow,spektom/incubator-airflow,mrkm4ntr/incubator-airflow,lxneng/incubator-airflow,yk5/incubator-airflow,CloverHealth/airflow,airbnb/airflow,wolfier/incubator-airflow,r39132/airflow,adamhaney/airflow,apache/airflow,mrkm4ntr/incubator-airflow,dhuang/incubator-airflow,apache/incubator-airflow,mtagle/airflow,wileeam/airflow,sergiohgz/incubator-airflow,cfei18/incubator-airflow,spektom/incubator-airflow,DinoCow/airflow,mistercrunch/airflow,dhuang/incubator-airflow,wooga/airflow,fenglu-g/incubator-airflow,yk5/incubator-airflow,apache/incubator-airflow,nathanielvarona/airflow,CloverHealth/airflow,cfei18/incubator-airflow,nathanielvarona/airflow,gtoonstra/airflow,Acehaidrey/incubator-airflow,Acehaidrey/incubator-airflow,airbnb/airflow,wileeam/airflow,sekikn/incubator-airflow,dhuang/incubator-airflow,bolkedebruin/airflow,bolkedebruin/airflow,sid88in/incubator-airflow,r39132/airflow,andyxhadji/incubator-airflow,lxneng/incubator-airflow,Fokko/incubator-airflow,mtagle/airflow,lyft/incubator-airflow,mtagle/airflow,adamhaney/airflow,apache/incubator-airflow,Acehaidrey/incubator-airflow,andyxhadji/incubator-airflow,mrkm4ntr/incubator-airflow,adamhaney/airflow,wooga/airflow,andyxhadji/incubator-airflow,wooga/airflow,mrkm4ntr/incubator-airflow,akosel/incubator-airflow,nathanielvarona/airflow,airbnb/airflow,danielvdende/incubator-airflow,andyxhadji/incubator-airflow,lxneng/incubator-airflow,sergiohgz/incubator-airflow,mistercrunch/airflow,apache/airflow,yk5/incubator-airflow,edgarRd/incubator-airflow,subodhchhabra/airflow,fenglu-g/incubator-airflow,jgao54/airflow,danielvdende/incubator-airflow,Fokko/incubator-airflow,sergiohgz/incubator-airflow,spektom/incubator-airflow,malmiron/incubator-airflow,bolkedebruin/airflow,wooga/airflow,danielvdende/incubator-airflow,apache/airflow,lxneng/incubator-airflow,cfei18/incubator-airflow,Acehaidrey/incubator-airflow,RealImpactAnalytics/airflow,subodhchhabra/airflow,nathanielvarona/airflow,sid88in/incubator-airflow,apache/airflow,DinoCow/airflow,malmiron/incubator-airflow,apache/airflow,criccomini/airflow,wileeam/airflow