Cannot build android project with .jks keystore

Hi there.

I recently went through the process of generating a new .jks and .pem file, as found in [issue 454](https://github.com/GoogleChromeLabs/bubblewrap/issues/454). I get an error saying my build failed due to an invalid keystore format. I am using Node v14.17.0, and the latest version of bubblerwrap.

Any insight into how to move forward with the build would be much appreciated.

**twa-manifest.json signing key section**

```
"signingKey": {
"path": "/Users/amac/company/repos/repo/keystore.jks",
"alias": "upload"
},
```

**How I generated the keystore**

```
keytool -genkeypair -alias upload -keyalg RSA -keysize 2048 -validity 9125 -keystore keystore.jks
```

**What I did**

```
bubblewrap build
```

**What I expected**

A new .apk and .aab to be generated

**What I actually get**