v2.0.21.1

This new release:

• collapses a number of redundant workflow wdl files into a singular workflow with branching logic depending on user options -- in particular, all of assemble_denovo_*.wdl has been collapsed into assemble_denovo.wdl with options defining whether to deplete, call isnvs, etc.
• upgrade viral-core to 2.0.21, which removes unaligned read deduplication (via MVicuna) as a default pass from the taxonomic depletion step. A separate WDL task (task_read_utils.rmdup_ubam) is now provided to perform this function and is added into to various workflows (such as assemble_denovo*) where this is useful, but omitted from others (assemble_refbased, demux_plus) where it is not.
• adds a fastq_to_ubam workflow that converts paired or single-end fastq reads to an unmapped bam file with appropriate read group headers [#57]
• bug fixes to multiqc task to allow for multiple input files that share the same basename (but different directory paths) -- this is a common scenario for nextseq flowcells or any other scenario where the exact same libraries are sequenced on multiple lanes of a flowcell. [#58]
• slight updates to build_augur_tree workflow [#48]