Fix CHANGELOG.md
Change 2.13.4 to 2.12.4, which is the version that it actually appears to be.
Bug Fixes:
- Allow scans with screen off on Android 8.1 (#637, David G. Young)
-### 2.13.4 / 2017-12-16
+### 2.12.4 / 2017-12-16
Bug Fixes:
- Fix performance problems when using identifiers 3-15 bytes caused by
