Update README.md

Added link for Metagenomics/Low_Biomass assay type

Author: bnovak32

README.md

@@ -18,7 +18,8 @@ Click on an assay type below for data processing information.
 - [Metagenomics](Metagenomics)  
   - [Remove human reads](Metagenomics/Remove_human_reads_from_raw_data)
   - [Estimate host reads](Metagenomics/Estimate_host_reads_in_raw_data)
-  - [Illumina](Metagenomics/Illumina)  
+  - [Illumina](Metagenomics/Illumina)
+  - [Low_Biomass](Metagenomics/Low_Biomass)
 - [(bulk) RNAseq](RNAseq)  
 - [single cell RNAseq](scRNAseq)  
 - [Methylation Sequencing](Methyl-Seq)