RunUMAP in Seurat not working: module 'umap' has no attribute 'UMAP'
This is resolved by installing the more recent version of the code from GitHub.

git clone https://github.com/lmcinnes/umap
cd umap
pip install --user -r requirements.txt
python setup.py install --user


As Peter said, this kind of question is best directed to the Issues page on their GitHub repository.