Failed to download libraries

## Description
Some files are failing to download after updating pytorch-engine to 0.20.0, the files aren't on your cloud instances so DJL just throws an error

### Expected Behavior
Downloads properly

### Error Message
```
ai.djl.engine.EngineException: Cannot download jni files: https://publish.djl.ai/pytorch/1.9.1/jnilib/0.20.0/linux-x86_64/cu111/libdjl_torch.so
at ai.djl.pytorch.jni.LibUtils.downloadJniLib(LibUtils.java:515)
at ai.djl.pytorch.jni.LibUtils.findJniLibrary(LibUtils.java:252)
at ai.djl.pytorch.jni.LibUtils.loadLibrary(LibUtils.java:80)
at ai.djl.pytorch.engine.PtEngine.newInstance(PtEngine.java:54)
at ai.djl.pytorch.engine.PtEngineProvider.getEngine(PtEngineProvider.java:40)
at ai.djl.engine.Engine.getEngine(Engine.java:186)
at ai.djl.engine.Engine.getInstance(Engine.java:141)
Caused by: java.io.FileNotFoundException: https://publish.djl.ai/pytorch/1.9.1/jnilib/0.20.0/linux-x86_64/cu111/libdjl_torch.so
at java.base/sun.net.www.protocol.http.HttpURLConnection.getInputStream0(HttpURLConnection.java:1993)
at java.base/sun.net.www.protocol.http.HttpURLConnection.getInputStream(HttpURLConnection.java:1589)
at java.base/sun.net.www.protocol.https.HttpsURLConnectionImpl.getInputStream(HttpsURLConnectionImpl.java:224)
at java.base/java.net.URL.openStream(URL.java:1161)
at ai.djl.util.Utils.openUrl(Utils.java:459)
at ai.djl.util.Utils.openUrl(Utils.java:443)
at ai.djl.pytorch.jni.LibUtils.downloadJniLib(LibUtils.java:509)
... 12 more
```

## How to Reproduce?
I've changed a simple application from
```
implementation("ai.djl.pytorch:pytorch-engine:0.16.0")
implementation("ai.djl.pytorch:pytorch-native-auto:1.9.1")
```
to
```
implementation("ai.djl.pytorch:pytorch-engine:0.20.0")
implementation("ai.djl.pytorch:pytorch-native-auto:1.9.1")
```
### Steps to reproduce
Just launch a simple program with this line to initiate the process to load the native libraries
```
Engine.getInstance()
```

## What have you tried to solve it?

These are missing files on your servers I assume, so nothing can be really done other than rollback...

## Environment Info
N/A

Start with ai.djl.pytorch.jni.LibUtils.downloadJniLib and the failing URL shown in the stack trace, then reproduce the problem with Engine.getInstance() using the listed dependency versions. Verify whether the 0.20.0 native library is available for linux-x86_64/cu111; done means the application can download and load it successfully.

Written by the indexing model from the issue text.