update mistral readme (microsoft#856)

## Describe your changes

## Checklist before requesting a review
- [ ] Add unit tests for this change.
- [ ] Make sure all tests can pass.
- [ ] Update documents if necessary.
- [ ] Lint and apply fixes to your code by running `lintrunner -a`
- [ ] Is this a user-facing change? If yes, give a description of this
change to be included in the release notes.

## (Optional) Issue link

examples/mistral/readme.md

@@ -1,8 +1,8 @@
 ## Prerequisites
 * transformers>=4.34.99
 * optimum
+* neural-compressor>=2.4.1
 * ort-nightly
-* git+https://github.com/intel/neural-compressor.git
 
 ## Installation
 ```bash