[UPDATE] Update ipython requirement

Updates the requirements on [ipython](https://github.com/ipython/ipython) to permit the latest version.
- [Release notes](https://github.com/ipython/ipython/releases)
- [Commits](https://github.com/ipython/ipython/compare/9.14.1...9.15.0)

---
updated-dependencies:
- dependency-name: ipython
  dependency-version: 9.15.0
  dependency-type: direct:development
...

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

pyproject.toml

@@ -44,7 +44,7 @@ dependencies = [
     "django-honeypot>=1.3.0,<2",
     "pydantic-extra-types>=2.11.1,<3.0.0",
     "ical>=12.0.0,<14.0.0",
-    "redis[hiredis]>=8.0.1,<9.0.0",
+    "redis[hiredis]>=6.4.0,<9.0.0",
     "environs[django]>=15.0.1,<16",
     "requests>=2.34.2,<3.0.0",
     "honcho>=2.0.0",
@@ -64,7 +64,7 @@ prod = [
 ]
 dev = [
     "django-debug-toolbar>=7.0.0,<8",
-    "ipython>=9.14.1,<10.0.0",
+    "ipython>=9.15.0,<10.0.0",
     "pre-commit>=4.6.0,<5.0.0",
     "ruff>=0.15.19,<1.0.0",
     "djhtml>=3.0.11,<4.0.0",