adding rasusa version 2.1.0

[erinyoung]

There's a new version of rasusa!

According to the release notes it looks like there are some new features.

I copied the files from 2.0.0 and changed the version ARG.

The full diff:

$ diff rasusa/2*/Dockerfile
3c3
< ARG RASUSA_VER="2.0.0"
---
> ARG RASUSA_VER="2.1.0"

Pull Request (PR) checklist:

• [x] Include a description of what is in this pull request in this message.
• [x] The dockerfile successfully builds to a test target for the user creating the PR. (i.e. docker build --tag samtools:1.15test --target test docker-builds/samtools/1.15 )
• [x] Directory structure as name of the tool in lower case with special characters removed with a subdirectory of the version number (i.e. spades/3.12.0/Dockerfile)
  • [x] (optional) All test files are located in same directory as the Dockerfile (i.e. shigatyper/2.0.1/test.sh)
• [x] Create a simple container-specific README.md in the same directory as the Dockerfile (i.e. spades/3.12.0/README.md)
  • [x] If this README is longer than 30 lines, there is an explanation as to why more detail was needed
• [x] Dockerfile includes the recommended LABELS
• [x] Main README.md has been updated to include the tool and/or version of the dockerfile(s) in this PR
• [x] Program_Licenses.md contains the tool(s) used in this PR and has been updated for any missing