opm alpha generate dockerfile does not work when directory trailing slash is informed

[camilamacedo86]

Description
$ opm alpha generate dockerfile <dir>/ does not work when directory trailing slash is informed

Workarround solution
Drop the trailing slash $ opm alpha generate dockerfile <dir>

Steps to reproduce

$ opm version
Version: version.Version{OpmVersion:"v1.19.1", GitCommit:"c426f78", BuildDate:"2021-10-11T15:26:23Z", GoOs:"darwin", GoArch:"amd64"}
$ mkdir operatorhubio
$ opm migrate quay.io/operatorhubio/catalog:latest operatorhubio
$ opm alpha generate dockerfile operatorhubio/