update README to use new concourse.ci address

Author: aclevername

README.md

@@ -23,7 +23,7 @@ In order to build the flake-detect checkout the repo and run `cd cmd/flake-detec
 
  ##### Examples
 
-`./flake-detector -team main -pipeline main -url https://ci.concourse.ci`
+`./flake-detector -team main -pipeline main -url https://ci.concourse-ci.org`
 
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