chore(requirements): pin all dependencies

Signed-off-by: Richard Steinmetz <richard@steinmetz.cloud>

requirements.txt

@@ -1,4 +1,31 @@
-sphinx
-rst2pdf
-pillow
-sphinx-rtd-theme
+alabaster==0.7.13
+Babel==2.12.1
+certifi==2022.12.7
+charset-normalizer==3.1.0
+docutils==0.17.1
+idna==3.4
+imagesize==1.4.1
+importlib-metadata==6.1.0
+Jinja2==3.0.3
+MarkupSafe==2.1.2
+packaging==23.0
+Pillow==8.4.0
+Pygments==2.14.0
+PyYAML==6.0
+reportlab==3.6.9
+requests==2.28.2
+rst2pdf==0.100
+smartypants==2.0.1
+snowballstemmer==2.2.0
+Sphinx==4.5.0
+sphinx-rtd-theme==1.2.0
+sphinxcontrib-applehelp==1.0.4
+sphinxcontrib-devhelp==1.0.2
+sphinxcontrib-htmlhelp==2.0.1
+sphinxcontrib-jquery==4.1
+sphinxcontrib-jsmath==1.0.1
+sphinxcontrib-phpdomain==0.9.0
+sphinxcontrib-qthelp==1.0.3
+sphinxcontrib-serializinghtml==1.1.5
+urllib3==1.26.15
+zipp==3.15.0