readme: use binary name instead of go run

Signed-off-by: Doug Hellmann <doug@doughellmann.com>

README.md

@@ -47,7 +47,7 @@ The `reviewers` sub-command generates a report showing the number of
 comments made across pull requests in a repository by each reviewer.
 
 ```console
-$ go run ./main.go  reviewers --org sphinx-contrib --repo datatemplates
+$ gh-review-stats reviewers --org sphinx-contrib --repo datatemplates
 Using config file: /Users/dhellmann/.gh-review-stats.yml
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