Bump ccxt from 4.1.76 to 4.2.15

Bumps [ccxt](https://github.com/ccxt/ccxt) from 4.1.76 to 4.2.15.
- [Release notes](https://github.com/ccxt/ccxt/releases)
- [Changelog](https://github.com/ccxt/ccxt/blob/master/CHANGELOG.md)
- [Commits](ccxt/ccxt@4.1.76...4.2.15)

---
updated-dependencies:
- dependency-name: ccxt
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <[email protected]>

requirements.txt

@@ -9,7 +9,7 @@ PyYAML==6.0.1
 tradingview-ta==3.3.0
 aiohttp>=3.8.0
 asyncpraw==7.7.1
-ccxt==4.1.76
+ccxt==4.2.15
 nltk==3.8.1
 transformers==4.35.0
 matplotlib==3.8.2