cm-push plugin installation fails with Helm 4
## Describe the bug
`cm-push` plugin installation fails with Helm 4.
## Expected behavior
`cm-push` plugin installation should work with both Helm 3 and Helm 4.
## Logs and/or screenshots
```bash
[INFO] --- trying to auto detect publish method...
[INFO] --- ... publish url looks like a Chart repository: will use push method (uses cm-push plugin)
[INFO] Installing cm-push plugin (version latest)...
Error: plugin source does not support verification. Use --verify=false to skip verification
Error: unknown command "cm-push" for "helm"
Run 'helm --help' for usage.
```
## Context & Configuration
Helm 4 verifies plugins signature by default but `cm-push` is not signed.
issue