docs: update supported Linux versions (#40177)

README.md

@@ -41,9 +41,9 @@ Each Electron release provides binaries for macOS, Windows, and Linux.
 * macOS (Catalina and up): Electron provides 64-bit Intel and ARM binaries for macOS. Apple Silicon support was added in Electron 11.
 * Windows (Windows 10 and up): Electron provides `ia32` (`x86`), `x64` (`amd64`), and `arm64` binaries for Windows. Windows on ARM support was added in Electron 5.0.8. Support for Windows 7, 8 and 8.1 was [removed in Electron 23, in line with Chromium's Windows deprecation policy](https://www.electronjs.org/blog/windows-7-to-8-1-deprecation-notice).
 * Linux: The prebuilt binaries of Electron are built on Ubuntu 20.04. They have also been verified to work on:
-  * Ubuntu 14.04 and newer
-  * Fedora 24 and newer
-  * Debian 8 and newer
+  * Ubuntu 18.04 and newer
+  * Fedora 32 and newer
+  * Debian 10 and newer
 
 ## Quick start & Electron Fiddle