Update FreeBSD 13 CI image to 13.1

13.0 is EoL.

Author: asomers

.cirrus.yml

@@ -15,7 +15,7 @@ task:
 task:
   name: nightly x86_64-unknown-freebsd-13
   freebsd_instance:
-    image: freebsd-13-0-release-amd64
+    image: freebsd-13-1-release-amd64
   setup_script:
     - pkg install -y curl
     - curl https://sh.rustup.rs -sSf --output rustup.sh