remove cirrus ci

.cirrus.yml

@@ -1,21 +0,0 @@
-env:
-  # Temporary workaround for error `error: sysinfo not supported on
-  # this platform` seen on FreeBSD platforms, affecting Rustup
-  #
-  # References: https://github.com/rust-lang/rustup/issues/2774
-  RUSTUP_IO_THREADS: 1
-
-task:
-  name: stable x86_64-unknown-freebsd-12
-  freebsd_instance:
-    image: freebsd-12-2-release-amd64
-  setup_script:
-    - pkg install -y curl gmake
-    - curl https://sh.rustup.rs -sSf --output rustup.sh
-    - sh rustup.sh -y --profile=minimal
-  build_script:
-    - . $HOME/.cargo/env
-    - cargo build
-  test_script:
-    - . $HOME/.cargo/env
-    - cargo test -p uucore -p coreutils