Update GitHub Sponsors count

According to https://github.com/sponsors/Homebrew

Update GitHub Sponsors count
da44aff4 · Jacob Ford · 62df7155 · da44aff4
Commit da44aff4 authored 4 years ago by Jacob Ford
--- a/README.md
+++ b/README.md
@@ -87,4 +87,4 @@ Homebrew is a member of the [Software Freedom Conservancy](https://sfconservancy

 [![Software Freedom Conservancy](https://sfconservancy.org/img/conservancy_64x64.png)](https://sfconservancy.org)

-Homebrew is generously supported by [Randy Reddig](https://github.com/ydnar) and 271 users via [GitHub Sponsors](https://github.com/sponsors/Homebrew).
+Homebrew is generously supported by [Randy Reddig](https://github.com/ydnar) and 439 users via [GitHub Sponsors](https://github.com/sponsors/Homebrew).