v4.4.0

Added

• Opening a workbook from a string or a stream. Excel::openString($content) reads a workbook
  held in memory (a database BLOB, an HTTP body, an S3/Flysystem read), and Excel::openStream($stream)
  reads it from an open stream resource (a URL via fopen(), php://memory, a Flysystem read stream).
  Both pick the reader by signature exactly like open(), so a string/stream carrying XLSX, XLS or CSV
  reads back identically to the same file on disk, and both accept the same $options as open().
  The content is copied to a temporary file (honouring Excel::setTempDir()), which is removed on
  script shutdown; the stream passed to openStream() is not closed. See
  docs/10-getting-started.md.
• Reading cell hyperlinks. Sheet::getHyperlinks() returns a sheet's hyperlinks keyed by the
  cell (or range) they are anchored to, each as ['link' => ..., 'location' => ..., 'display' => ..., 'tooltip' => ...]. External targets are resolved from the sheet relationships file; internal links
  expose their in-document location. A sheet without hyperlinks returns an empty array. See
  docs/16-sheet-metadata.md.
• Reading workbook document properties. Excel::getProperties() returns the core
  (docProps/core.xml) and application (docProps/app.xml) properties as one associative array with
  normalised keys — creator, lastModifiedBy, created, modified, title, application,
  company, ... Only the properties present in the file are returned; a workbook without a docProps
  part returns an empty array. See docs/12-advanced-reading.md.