finch attach not available as top level command

[weikequ]

Describe the bug
Finch should make finch attach available as a top level command to keep parity with nerdctl. It is currently available as a subcommand as finch container attach

Steps to reproduce

• finch attach --help

Expected behavior

$ finch attach --help
Attach stdin, stdout, and stderr to a running container. For example:

Screenshots or logs

• FATA[0000] unknown command "attach" for "finch"

[haytok]

Hi, Team
Could you assign this issue to me ?
I'll address this issue.

[haytok]

This feature can be added, but we can't implement the test because of a bug in nerdctl.

• failed to attach to the container: failed to open stdout fifo: error creating fifo binary:///usr/local/bin/nerdctl?_NERDCTL_INTERNAL_LOGGING=%2Fvar%2Flib%2Fnerdctl%2F1935db59: no such file or directory containerd/nerdctl#2877
• shimv2: support attachable binary I/O containerd/containerd#10020

Further details are discussed at a below PR.

• fix: add finch attach command #847