add support for excludes in input dir

This adds support for `--include` and `--exclude` for directory inputs.

For instance, this is what you would want to use when passing dagger
repository as an input:

```
inputs:
    repository:
        dir:
            path: .
            exclude:
                - '**/node_modules'
                - cmd/dagger/dagger
                - cmd/dagger/dagger-debug
```

Signed-off-by: Andrea Luzzardi <aluzzardi@gmail.com>

state/state.go

@@ -26,7 +26,7 @@ type State struct {
 // Cue module containing the environment plan
 // The input's top-level artifact is used as a module directory.
 func (s *State) PlanSource() Input {
-	return DirInput(s.Plan, []string{"*.cue", "cue.mod"})
+	return DirInput(s.Plan, []string{"*.cue", "cue.mod"}, []string{})
 }
 
 func (s *State) SetInput(key string, value Input) error {