The cli command exec not handle in a coherent way the repository path
when a directory or filename is given for the pipeline.
` woodpecker-cli exec [command options] [path/to/.woodpecker.yaml]`
If the path to the pipeline is a file in the `.woodpecker` directory,
for example: `.woodpecker/pipeline.yaml`,
the repository path will be: `.woodpecker`
If the path to the pipeline yaml is a directory with more than one
level, for example `ci/woodpecker/`,
the repository path will be: `ci`
In order not to break the old behavior we added a new option to put the
root directory of the repository:
~~~
woodpecker-cli exec --local --repo-path . --pipeline-event manual
.woodpecker/build.yml
~~~
