docs: fix another broken link in the coc

The markdown generation of the upstream Contributor Covenant page seems
to have some issues.

 CODE_OF_CONDUCT.md | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/CODE_OF_CONDUCT.md b/CODE_OF_CONDUCT.md
index 077ddfb..c0eb20f 100644
--- a/CODE_OF_CONDUCT.md
+++ b/CODE_OF_CONDUCT.md
@@ -75,4 +75,4 @@ ban from community spaces, a permanent ban from community spaces, etc.
 This Code of Conduct is adapted from the
 [Contributor Covenant](https://www.contributor-covenant.org/),
 version 2.1, available at
-[https://www.contributor-covenant.org/version/2/1/code_of_conduct.html][v2.1].
+https://www.contributor-covenant.org/version/2/1/code_of_conduct.html.