syntax error near unexpected token `then'

Today the steps that install envsubst in my circleci pipelines turned up broken, error:

```
/bin/bash: -c: line 6: syntax error near unexpected token `then'
Exited with code exit status 2
```
The only thing I do in my .yml file is call the orb:

```
orbs:
envsubst: sawadashota/envsubst@volatile
```

and later in a step of the command I perform the installation

```
steps:
- checkout
- envsubst/install
```

Reviewing it, I realized that yesterday the release was published with version 1.4.2 for the circleci orb. I checked the commits of the merged [version](https://github.com/a8m/envsubst/releases/tag/v1.4.2) yesterday but I can't find anything directly related that is causing the error. Can you give me a hand?

https://circleci.com/developer/orbs/orb/sawadashota/envsubst

The issue is about a bash syntax error in the CircleCI orb installation script. Look at the orb's source in the repository, likely under a directory like .circleci or in the orb definition. Check the install command or script for bash syntax issues, particularly around 'then' tokens in conditional statements. Test the script locally in a bash shell to reproduce the error. The fix involves correcting the bash script syntax.

索引モデルが issue の本文から書いたものです。