Bump gunicorn from 23.0.0 to 25.3.0 in /requirements

Bumps [gunicorn](https://github.com/benoitc/gunicorn) from 23.0.0 to 25.3.0.
- [Release notes](https://github.com/benoitc/gunicorn/releases)
- [Commits](benoitc/gunicorn@23.0.0...25.3.0)

---
updated-dependencies:
- dependency-name: gunicorn
  dependency-version: 25.3.0
  dependency-type: direct:production
  update-type: version-update:semver-major
...

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

Author: dependabot[bot]

requirements/requirements-prod.in

@@ -32,7 +32,7 @@ Flask==2.3.2
 Flask-RESTful==0.3.9
 gdata==2.0.18
 greenlet==3.0.3
-gunicorn==23.0.0
+gunicorn==25.3.0
 hiredis==2.3.2
 html2text==2020.1.16
 icalendar==4.0.9

requirements/requirements-prod.txt

@@ -412,9 +412,9 @@ greenlet==3.0.3 \
     # via
     #   -r requirements-prod.in
     #   sqlalchemy
-gunicorn==23.0.0 \
-    --hash=sha256:ec400d38950de4dfd418cff8328b2c8faed0edb0d517d3394e457c317908ca4d \
-    --hash=sha256:f014447a0101dc57e294f6c18ca6b40227a4c90e9bdb586042628030cba004ec
+gunicorn==25.3.0 \
+    --hash=sha256:cacea387dab08cd6776501621c295a904fe8e3b7aae9a1a3cbb26f4e7ed54660 \
+    --hash=sha256:f74e1b2f9f76f6cd1ca01198968bd2dd65830edc24b6e8e4d78de8320e2fe889
     # via -r requirements-prod.in
 hiredis==2.3.2 \
     --hash=sha256:01b6c24c0840ac7afafbc4db236fd55f56a9a0919a215c25a238f051781f4772 \