Only some refactoring.

* You can now use environment variable in the `zotero-bibliography`

  metadata field, using the `${varname}` syntax.
* The `zotero-bibliography` file can now also be written as
  BibTeX and BibLaTeX if you are running Pandoc >= v2.17.
  This is *not* recommended though.
* Made citation key parsing for the Web API more robust.

* No longer shows cryptic error messages if an item cannot be found
  and you are using the most recent version of zotxt.
* Should now run in Pandoc < v2.7.
* Citation keys are now only interpreted as Zotero item IDs
  if they look like Zotero item IDs.
* Fixed typos in error messages.
* Corrected the required version in the README.

* When looking up citation keys via the Zotero Web API, they must now
  be translatable into at least two search terms.

* No longer looks up bibliographic data of sources that can be found …

…in the `references` metadata field or BibTeX, CSL JSON, or CSL YAML bibliography files.

* Now searches for citations in the document's metadata fields, too; in *all* of them, this may change in future releases.
* Support for connecting to Zotero via the [Zotero Web API](https://www.zotero.org/support/dev/web_api/v3/start) in addition to/instead of [zotxt](https://github.com/egh/zotxt).
* Support for **pandoc**'s `--resource-path` option.
* Atomic update of the bibliography file.
* The bibliography file can now be in CSL YAML format, too.

* Works with *all* releases of Pandoc ≥ v2.0.2 again.
* Users can now declare what types of citation keys they use (this fixes issue #6).
* No longer throws away all but the first bibliography file set in the `bibliography` metadata field if `zotero-bibliography` is set.
* No longer fails to parse the `bibliography` metadata field if run with Pandoc ≤ v2.11, only a single file was set, and that file was set a YAML scalar.
* Now prints meaningful error messages, rather than stack traces (save for a few edge cases).

Dotting the i's before v1.1.

Disabled debugging mode.

Error messages distinguish more clearly between (some) bugs and run-t…

…ime errors.

* Somewhere along the way, `pandoc-zotxt.lua` stopped parsing the `bibliography` metadata field if (1) it was run by Pandoc <v2.11 and (2) only a single bibliography file was given as a YAML scalar. This is fixed in this release.
* Made YAML-support more robust.

v1.1.0b6

No relevant change. This is only to address a minor issue with a release script.

v1.1.0b4

* Adds support for the Zotero Web API.
* Fixes support for Pandoc < v2.16.
* Hopefully addresses issue #7.
* Makes code even more defensive.
* Test suite now tests older Pandoc versions.
* Better source documentation.

See release for details.

Better YAML handling.

Also improvements to the installer and some fixes.

Experimental support for YAML bibliography files (and more).