2.3.0

• Add optional waveforms column to the Units table.
• Add optional strain field to Subject.
• Add to DecompositionSeries an optional DynamicTableRegion called
  source_channels.
• Add to ImageSeries an optional link to Device.
• Add optional continuity field to TimeSeries.
• Add optional filtering attribute to ElectricalSeries.
• Clarify documentation for electrode impedance and filtering.
• Add description of extra fields.
• Set the stimulus_description for IZeroCurrentClamp to have the
  fixed value N/A.
• Update hdmf-common-schema from 1.1.3 to version 1.5.0.
  • The HDMF-experimental namespace was added, which includes the
    ExternalResources and EnumData data types. Schema in the
    HDMF-experimental namespace are experimental and subject to breaking
    changes at any time.
  • Added experimental data type ExternalResources for storing
    ontology information / external resource references.
  • Added experimental data type EnumData to store data from a set
    of fixed values.
  • Changed dtype for datasets within CSRMatrix from 'int' to
    'uint' and added missing data_type_inc: Container to the
    CSRMatrix type.
  • Added data type SimpleMultiContainer, a Container for storing
    other Container and Data objects together.
  • Added data type AlignedDynamicTable, a DynamicTable type with
    support for categories (or sub-headings) each described by a
    separate DynamicTable.
  • Fixed missing dtype for VectorIndex.
  • VectorIndex now extends VectorData instead of Index.
  • Removed unused and non-functional Index data type.
  • See
    https://hdmf-common-schema.readthedocs.io/en/latest/format_release_notes.html
    for full release notes.