Bump readme-renderer from 25.0 to 26.0 (#637)

Bumps [readme-renderer](https://github.com/pypa/readme_renderer) from 25.0 to 26.0.
- [Release notes](https://github.com/pypa/readme_renderer/releases)
- [Changelog](https://github.com/pypa/readme_renderer/blob/master/CHANGES.rst)
- [Commits](pypa/readme_renderer@25.0...26.0)

Signed-off-by: dependabot-preview[bot] <support@dependabot.com>

Co-authored-by: dependabot-preview[bot] <27856297+dependabot-preview[bot]@users.noreply.github.com>

Author: dependabot-preview[bot]

requirements.txt

@@ -490,9 +490,9 @@ pyyaml==5.3.1 \
     --hash=sha256:cc8955cfbfc7a115fa81d85284ee61147059a753344bc51098f3ccd69b0d7e0c \
     --hash=sha256:d13155f591e6fcc1ec3b30685d50bf0711574e2c0dfffd7644babf8b5102ca1a \
     # via -r requirements.in, flask-flatpages
-readme-renderer==25.0 \
-    --hash=sha256:1b6d8dd1673a0b293766b4106af766b6eff3654605f9c4f239e65de6076bc222 \
-    --hash=sha256:e67d64242f0174a63c3b727801a2fff4c1f38ebe5d71d95ff7ece081945a6cd4 \
+readme-renderer==26.0 \
+    --hash=sha256:cbe9db71defedd2428a1589cdc545f9bd98e59297449f69d721ef8f1cfced68d \
+    --hash=sha256:cc4957a803106e820d05d14f71033092537a22daa4f406dfbdd61177e0936376 \
     # via -r requirements.in, twine
 redis==3.4.1 \
     --hash=sha256:0dcfb335921b88a850d461dc255ff4708294943322bd55de6cfd68972490ca1f \