ci: add aarch64_be-unknown-linux-gnu

Signed-off-by: Sam James <sam@gentoo.org>

Author: thesamesam

.github/workflows/crossdev.yml

@@ -19,6 +19,7 @@ jobs:
         target:
           - target: aarch64-unknown-linux-gnu
           - target: aarch64-unknown-linux-musl
+          - target: aarch64_be-unknown-linux-gnu
           - target: alpha-unknown-linux-gnu
           - target: arm-unknown-linux-gnueabi
           - target: arm-unknown-linux-gnueabihf