Bump matminer from 0.6.2 to 0.6.3

Bumps [matminer](https://github.com/hackingmaterials/matminer) from 0.6.2 to 0.6.3.
- [Release notes](https://github.com/hackingmaterials/matminer/releases)
- [Changelog](https://github.com/hackingmaterials/matminer/blob/master/docs/changelog.html)
- [Commits](hackingmaterials/matminer@v0.6.2...v0.6.3)

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

Author: dependabot-preview[bot]

requirements.txt

@@ -1,5 +1,5 @@
 # Direct requirements of this project alone
-matminer==0.6.2
+matminer==0.6.3
 pymatgen==2020.01.28
 xgboost==0.80
 tpot==0.11.0