Remove unused docs requirements and bump versions

Author: domdfcoding

doc-source/requirements.txt

@@ -1,21 +1,16 @@
-default-values>=0.5.0
-extras-require>=0.2.0
-furo>=2020.11.19b18
-html-section>=0.1.0
-pyyaml>=5.3.1
-repo-helper-sphinx-theme>=0.0.2
-seed-intersphinx-mapping>=0.3.1
+default-values>=0.6.0
+extras-require>=0.5.0
+furo==2021.06.18b36
+html-section>=0.3.0
+seed-intersphinx-mapping>=1.2.2
 sphinx>=3.0.3
 sphinx-copybutton>=0.2.12
-sphinx-debuginfo>=0.1.0
+sphinx-debuginfo>=0.2.2
 sphinx-favicon>=0.2
-sphinx-licenseinfo>=0.1.1
+sphinx-licenseinfo>=0.3.1
 sphinx-notfound-page>=0.7.1
 sphinx-prompt>=1.1.0
 sphinx-pyproject>=0.1.0
-sphinx-tabs>=1.1.13
-sphinx-toolbox>=3.0.0a4
-sphinxcontrib-httpdomain>=1.7.0
+sphinx-toolbox>=3.5.0
 sphinxemoji>=0.1.6
-tabulate>=0.8.7
-toctree-plus>=0.5.0
+toctree-plus>=0.6.1