Release v0.2.0

Make the CLI give better error messages

e.g.

```
❯ ./target/debug/jdp check data/invalid/no-steps-in-stage/Jenkinsfile

data/invalid/no-steps-in-stage/Jenkinsfile
------------------------------------------
1:     agent any
2:     stages {
3:         stage('Build') {
4:         }
  ---------^

Failed to parse: missing required syntax
```