Move Vagrant-based tests from GitHub Actions to Cirrus CI

Cirrus CI supports nested virtualization and free to use from open
source projects. runc has been using the service since
https://github.com/opencontainers/runc/pull/3088.

Signed-off-by: Kazuyoshi Kato <katokazu@amazon.com>

script/resize-vagrant-root.sh

@@ -0,0 +1,40 @@
+#!/usr/bin/env bash
+
+#   Copyright The containerd Authors.
+
+#   Licensed under the Apache License, Version 2.0 (the "License");
+#   you may not use this file except in compliance with the License.
+#   You may obtain a copy of the License at
+
+#       http://www.apache.org/licenses/LICENSE-2.0
+
+#   Unless required by applicable law or agreed to in writing, software
+#   distributed under the License is distributed on an "AS IS" BASIS,
+#   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+#   See the License for the specific language governing permissions and
+#   limitations under the License.
+
+set -eu -o pipefail
+
+# Rocky Linux doesn't have growpart by default.
+(growpart -h > /dev/null) || dnf -y install cloud-utils-growpart
+
+df_line=$(df -T / | grep '^/dev/')
+if [[ "$df_line" =~ ^/dev/([a-z]+)([0-9+]) ]]; then
+    dev="${BASH_REMATCH[1]}"
+    part="${BASH_REMATCH[2]}"
+    growpart "/dev/$dev" "$part"
+
+    fstype=$(echo "$df_line" | awk '{print $2}')
+    if [[ "$fstype" = 'btrfs' ]]; then
+        btrfs filesystem resize max /
+    elif [[ "$fstype" = 'xfs' ]]; then
+        xfs_growfs -d /
+    else
+        echo "Unknown filesystem: $df_line"
+        exit 1
+    fi
+else
+    echo "Failed to parse: $df_line"
+    exit 1
+fi