[FAB-9281] Update check_license.sh, ^build/ -> ^.build/
[FAB-9281] Update check_license.sh, ^build/ -> ^.build/

Given renaming of build/ to .build/, update the license
checking script to refer to the new name.

Change-Id: I20eb42462c9b45b7a241ada29f5abfd635fbc99d
Signed-off-by: Robert P. J. Day <01aa5cd9a29907856ec6ddeebcb643ede4c45b8b@crashcourse.ca>

stemlending/fabric,binhn/fabric,manish-sethi/fabric-sidedb,manish-sethi/fabric-sidedb,muralisrini/fabric,hyperledger/fabric,manish-sethi/fabric-sidedb,xixuejia/fabric,stemlending/fabric,xixuejia/fabric,jimthematrix/fabric,manish-sethi/fabric-sidedb,manish-sethi/fabric,muralisrini/fabric,xixuejia/fabric,jimthematrix/fabric,manish-sethi/fabric,manish-sethi/fabric-sidedb,muralisrini/fabric,binhn/fabric,hyperledger/fabric,stemlending/fabric,binhn/fabric,manish-sethi/fabric-sidedb,stemlending/fabric,manish-sethi/fabric-sidedb