Revise development support information in README (#9583)

Author: aclark4life

README.md

@@ -9,8 +9,10 @@
 Pillow is the friendly PIL fork by [Jeffrey 'Alex' Clark and
 contributors](https://github.com/python-pillow/Pillow/graphs/contributors).
 PIL is the Python Imaging Library by Fredrik Lundh and contributors.
-As of 2019, Pillow development is
-[supported by Tidelift](https://tidelift.com/subscription/pkg/pypi-pillow?utm_source=pypi-pillow&utm_medium=readme&utm_campaign=enterprise).
+Development is supported by:
+- [Tidelift](https://tidelift.com/subscription/pkg/pypi-pillow?utm_source=pypi-pillow&utm_medium=readme&utm_campaign=enterprise) (since 2018)
+- [Thanks.dev](https://thanks.dev) (since 2023)
+- [GitHub Sponsors](https://github.com/sponsors/python-pillow) (since 2026)
 
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