Add MMseqs2 clarification

README.md

@@ -27,7 +27,7 @@ Python dependencies available through `pip` are provided in `requirements.txt`.
 OpenFold depends on `openmm==7.5.1` and `pdbfixer`, which are only available 
 via `conda`. For producing sequence alignments, you'll also need
 `kalign`, the [HH-suite](https://github.com/soedinglab/hh-suite), and one of 
-{`jackhmmer`, [MMseqs2](https://github.com/soedinglab/mmseqs2)} installed on
+{`jackhmmer`, [MMseqs2](https://github.com/soedinglab/mmseqs2) (nightly build)} installed on
 on your system. Finally, some download scripts require `aria2c`.
 
 For convenience, we provide a script that installs Miniconda locally, creates a