Bump version and add back a paragraph that was lost in a merge.

README.md

@@ -11,14 +11,23 @@ S et al. High-resolution sweep metagenomics using fast probabilistic
 inference [version 2; peer review: 2 approved]. Wellcome Open Res
 2021, 5:14 (https://doi.org/10.12688/wellcomeopenres.15639.2)"
 
+To cite a specific version of mSWEEP, visit the [releases
+page](https://github.com/PROBIC/mSWEEP/releases) and find the doi for
+the version of the program that you used. Then, cite the version (v1.5.0
+in the example) as "Tommi Mäklin, & Antti
+Honkela. (2021). PROBIC/mSWEEP: mSWEEP v1.5.0 (15 October 2021)
+(v1.5.0). Zenodo. (https://doi.org/10.5281/zenodo.5571944)". Please
+also cite the [mSWEEP article](https://doi.org/10.12688/wellcomeopenres.15639.2)
+if you use mSWEEP.
+
 You can also watch a talk from [ISMB/ECCB
 2019](https://www.iscb.org/ismbeccb2019) presenting the main results
 from the mSWEEP paper [in YouTube](https://www.youtube.com/watch?v=VDfChoJwSKg).
 
 # Installation
 mSWEEP can be obtained either in the form of a precompiled binary
-* [Linux 64-bit binary](https://github.com/PROBIC/mSWEEP/releases/download/v1.5.2/mSWEEP_linux-v1.5.2.tar.gz)
-* [macOS 64-bit binary](https://github.com/PROBIC/mSWEEP/releases/download/v1.5.2/mSWEEP_macOS-v1.5.2.tar.gz)
+* [Linux 64-bit binary](https://github.com/PROBIC/mSWEEP/releases/download/v1.6.1/mSWEEP_linux-v1.6.1.tar.gz)
+* [macOS 64-bit binary](https://github.com/PROBIC/mSWEEP/releases/download/v1.6.1/mSWEEP_macOS-v1.6.1.tar.gz)
 or by following the instructions below for compiling mSWEEP from source.
 
 In addition to mSWEEP, you will need to install either [Themisto