Iqtree3 3.1.2

[RaheelSyedAhmed]

Pull Request (PR) checklist:

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

This PR includes an update to the docker build-files for IQTREE3. It introduces a directory for version 3.1.2 that includes a Dockerfile updated for the correct version and the README.md from the prior version since no syntax changes were introduced. The main README.md versions dropdown includes version 3.1.2 now, and the Program License URL was checked to ensure it's under the same licensure.