Don't create basename directory if copying directory into existing one

[BetaHuhn]

Current implementation/problem

I want to copy the contents of a directory into another existing directory. Right now, because of these lines:

toolkit/packages/io/src/io.ts

Lines 47 to 51 in 4dd900d

	// If dest is an existing directory, should copy inside.
	const newDest: string =
	destStat && destStat.isDirectory()
	? path.join(dest, path.basename(source))
	: dest

The files/folders in the source directory get copied into another folder (the basename of the source path) inside the target directory.

For example, I want to copy the directory .github/ISSUE_TEMPLATE/ to issues/. With the current version of @actions/io the files will end up in issues/ISSUE_TEMPLATE instead of issues/ if issues/ already exists.

Describe the enhancement

Add an option to disable this behavior and copy all files from one directory into the other without creating the basename folder.

Code Snippet

const newDest: string =
    destStat && destStat.isDirectory() && copyInside // Add this new option
      ? path.join(dest, path.basename(source))
      : dest

Additional information

If there's another way of achieving this, please let me know. If not, I would be willing to create a PR for this.

[BetaHuhn]

Great, thanks!