build(deps): bump sphinxcontrib-applehelp in /tools/base

Bumps [sphinxcontrib-applehelp](https://github.com/sphinx-doc/sphinxcontrib-applehelp) from 1.0.8 to 2.0.0.
- [Release notes](https://github.com/sphinx-doc/sphinxcontrib-applehelp/releases)
- [Changelog](https://github.com/sphinx-doc/sphinxcontrib-applehelp/blob/master/CHANGES.rst)
- [Commits](sphinx-doc/sphinxcontrib-applehelp@1.0.8...2.0.0)

---
updated-dependencies:
- dependency-name: sphinxcontrib-applehelp
  dependency-type: direct:production
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <[email protected]>

tools/base/requirements.txt

@@ -1267,9 +1267,9 @@ sphinx-rtd-theme==2.0.0 \
     --hash=sha256:bd5d7b80622406762073a04ef8fadc5f9151261563d47027de09910ce03afe6b \
     --hash=sha256:ec93d0856dc280cf3aee9a4c9807c60e027c7f7b461b77aeffed682e68f0e586
     # via envoy-docs-sphinx-runner
-sphinxcontrib-applehelp==1.0.8 \
-    --hash=sha256:c40a4f96f3776c4393d933412053962fac2b84f4c99a7982ba42e09576a70619 \
-    --hash=sha256:cb61eb0ec1b61f349e5cc36b2028e9e7ca765be05e49641c97241274753067b4
+sphinxcontrib-applehelp==2.0.0 \
+    --hash=sha256:2f29ef331735ce958efa4734873f084941970894c6090408b079c61b2e1c06d1 \
+    --hash=sha256:4cd3f0ec4ac5dd9c17ec65e9ab272c9b867ea77425228e68ecf08d6b28ddbdb5
     # via
     #   -r requirements.in
     #   sphinx