chore(deps): update flask dependency range to include v3 (#288)

This PR contains the following updates:

| Package | Change | Age | Adoption | Passing | Confidence |
|---|---|---|---|---|---|
| flask ([changelog](https://flask.palletsprojects.com/changes/)) | `>=1.0,<3.0` -> `>=1.0,<4.0` | [![age](https://developer.mend.io/api/mc/badges/age/pypi/flask/3.0.0?slim=true)](https://docs.renovatebot.com/merge-confidence/) | [![adoption](https://developer.mend.io/api/mc/badges/adoption/pypi/flask/3.0.0?slim=true)](https://docs.renovatebot.com/merge-confidence/) | [![passing](https://developer.mend.io/api/mc/badges/compatibility/pypi/flask/2.3.3/3.0.0?slim=true)](https://docs.renovatebot.com/merge-confidence/) | [![confidence](https://developer.mend.io/api/mc/badges/confidence/pypi/flask/2.3.3/3.0.0?slim=true)](https://docs.renovatebot.com/merge-confidence/) |

Author: HKWinterhalter

setup.py

@@ -51,7 +51,7 @@
     package_dir={"": "src"},
     python_requires=">=3.5, <4",
     install_requires=[
-        "flask>=1.0,<3.0",
+        "flask>=1.0,<4.0",
         "click>=7.0,<9.0",
         "watchdog>=1.0.0",
         "gunicorn>=19.2.0; platform_system!='Windows'",