oclif.manifest.json is not in the source tree

`oclif.manifest.json` does not exist is the source tree. It is handled via the pre/postpack scripts, and therefore shall be removed from `package.json` `.files` list. Having it there breaks packaging tools.

```patch
--- a/package.json
+++ b/package.json
@@ -55,7 +55,6 @@
"files": [
"/bin",
"/src",
- "/oclif.manifest.json",
"/package-lock.json"
],
"homepage": "https://github.com/adobe/aio-cli",
````

Open package.json and inspect the pre/postpack scripts that handle oclif.manifest.json. Confirm how the files list is used by the packaging tools, then verify that the source tree is packaged without expecting this generated manifest. Done means packaging completes without the reported error.

Written by the indexing model from the issue text.