README: fix CC BY license name

Change-Id: Idf3c4427426e3cb74c7749762f2b4f621cf82dba
GitHub-Last-Rev: 86f51a5
GitHub-Pull-Request: golang#68518
Reviewed-on: https://go-review.googlesource.com/c/go/+/599515
Auto-Submit: Ian Lance Taylor <iant@google.com>
Reviewed-by: Dmitri Shuralyov <dmitshur@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: Ian Lance Taylor <iant@google.com>

README.md

@@ -4,7 +4,7 @@ Go is an open source programming language that makes it easy to build simple,
 reliable, and efficient software.
 
 ![Gopher image](https://golang.org/doc/gopher/fiveyears.jpg)
-*Gopher image by [Renee French][rf], licensed under [Creative Commons 4.0 Attributions license][cc4-by].*
+*Gopher image by [Renee French][rf], licensed under [Creative Commons 4.0 Attribution license][cc4-by].*
 
 Our canonical Git repository is located at https://go.googlesource.com/go.
 There is a mirror of the repository at https://github.com/golang/go.