Fix url in WORKSPACE snippet (#145)

.github/generate-notes.sh

diff --git a/.github/generate-notes.sh b/.github/generate-notes.sh
index 6dab63b..4b07f7f 100755
--- a/.github/generate-notes.sh
+++ b/.github/generate-notes.sh
@@ -23,7 +23,7 @@
     sha256 = "$sha256",
     strip_prefix = "buildifier-prebuilt-$new_version",
     urls = [
-        "http://github.com/keith/buildifier-prebuilt/archive/$new_version.tar.gz",
+        "https://github.com/keith/buildifier-prebuilt/releases/download/$new_version/buildifier-prebuilt.$new_version.tar.gz",
     ],
 )