[epiphany] Update README.md: flathub is back!

[Michael Catanzaro <mcatanzaro src gnome org>]

commit a8fcbb17c04c6fdce32a69e99b1e51a095e59157
Author: Michael Catanzaro <mcatanzaro gnome org>
Date:   Fri May 8 21:10:23 2020 +0000

    Update README.md: flathub is back!

 README.md | 6 ++----
 1 file changed, 2 insertions(+), 4 deletions(-)
---
diff --git a/README.md b/README.md
index 8c110c2b1..85fa4157e 100644
--- a/README.md
+++ b/README.md
@@ -12,10 +12,8 @@ Epiphany is opinionated.
 Epiphany is designed for Linux systems. The recommended way to install Epiphany
 is via [Flatpak](https://www.flatpak.org/). You may:
 
- * ~~[Download the latest stable version from 
Flathub](https://flathub.org/repo/appstream/org.gnome.Epiphany.flatpakref)
-   (recommended).~~ Flathub downloads are currently not recommended due to major
-   security problems discovered in the application runtime. We expect this
-   situation to be improved in the future. In the meantime, do not use.
+ * [Download the latest stable version from 
Flathub](https://flathub.org/repo/appstream/org.gnome.Epiphany.flatpakref)
+   (recommended).
  * [Download Epiphany Technology Preview](https://webkitgtk.org/epiphany-tech-preview)
    if you are adventurous and want to help test tomorrow's Epiphany today. It
    is **not stable**.