whisper : add version function (#3289)

* whisper : add version function

This commit adds a version function to the whisper API.

The motivation for this is that it might be convenient to have a way to
programmatically check the version.

Example usage:
```c++
printf("Using whisper version: %s\n", whisper_version());
```
Will output:
```console
Using whisper version: 1.7.6
```

* examples : add version to android example CMakeLists.txt

include/whisper.h

@@ -198,6 +198,8 @@ extern "C" {
         float samples_overlap;         // Overlap in seconds when copying audio samples from speech segment.
     } whisper_vad_params;
 
+    WHISPER_API const char * whisper_version(void);
+
     // Various functions for loading a ggml whisper model.
     // Allocate (almost) all memory needed for the model.
     // Return NULL on failure