Add 1.68.1 patch release

https://blog.rust-lang.org/inside-rust/2023/03/20/1.68.1-prerelease.html

Author: dtolnay

scripts/update-revs.sh

@@ -10,7 +10,7 @@ fi
 patch_releases=(
     1.12.1 1.15.1 1.22.1 1.24.1 1.26.1 1.26.2 1.27.1 1.27.2 1.29.1 1.29.2 1.30.1
     1.31.1 1.34.1 1.34.2 1.41.1 1.43.1 1.44.1 1.45.1 1.45.2 1.52.1 1.56.1 1.58.1
-    1.62.1 1.66.1 1.67.1
+    1.62.1 1.66.1 1.67.1 1.68.1
 )
 
 releases() {