chore: bump docs requirements dependabot complains about

Author: dvarrazzo

doc/requirements.txt

@@ -8,7 +8,7 @@ alabaster==0.7.13
     # via sphinx
 babel==2.12.1
     # via sphinx
-certifi==2022.12.7
+certifi>=2023.7.22
     # via requests
 charset-normalizer==3.1.0
     # via requests
@@ -26,7 +26,7 @@ packaging==23.1
     # via sphinx
 pygments==2.15.0
     # via sphinx
-requests==2.28.2
+requests==2.31.0
     # via sphinx
 snowballstemmer==2.2.0
     # via sphinx