feat: prepare APA citation style plugin

Author: schnaitter

_config.yml

@@ -23,6 +23,8 @@ bibtex_bibfiles:
 
 # reference style
 sphinx:
+  extra_extensions:
+    #- sphinx_apa_references
   config:
     bibtex_reference_style: author_year
     html_show_copyright: false

requirements.txt

@@ -138,6 +138,7 @@ sphinx-jupyterbook-latex==1.0.0
 sphinx-multitoc-numbering==0.1.3
 sphinx-thebe==0.3.1
 sphinx-togglebutton==0.3.2
+sphinx_apa_references @ git+https://github.com/quadriga-dk/Sphinx-APA-References.git@d80f2b6edb18bb3c4c03507fe3e46e8ed1fd8ec6
 sphinx_design==0.5.0
 sphinx_external_toc==1.0.1
 sphinxcontrib-applehelp==1.0.8
@@ -151,6 +152,7 @@ SQLAlchemy==2.0.28
 srsly==2.4.8
 stack-data==0.6.3
 tabulate==0.9.0
+teachbooks==0.2.3
 terminado==0.18.0
 tesseract==0.1.3
 thinc==8.2.3