Revert "README.md bump version to 0.6.0"

This reverts commit 2784260.

README.md

@@ -13,8 +13,8 @@ _Read more about Dangerzone in the [official site](https://dangerzone.rocks/abou
 ## Getting started
 
 ### MacOS
-- Download [Dangerzone 0.6.0 for Mac (Apple Silicon CPU)](https://github.com/freedomofpress/dangerzone/releases/download/v0.6.0/Dangerzone-0.6.0-arm64.dmg)
-- Download [Dangerzone 0.6.0 for Mac (Intel CPU)](https://github.com/freedomofpress/dangerzone/releases/download/v0.6.0/Dangerzone-0.6.0-i686.dmg)
+- Download [Dangerzone 0.5.1 for Mac (Apple Silicon CPU)](https://github.com/freedomofpress/dangerzone/releases/download/v0.5.1/Dangerzone-0.5.1-arm64.dmg)
+- Download [Dangerzone 0.5.1 for Mac (Intel CPU)](https://github.com/freedomofpress/dangerzone/releases/download/v0.5.1/Dangerzone-0.5.1-i686.dmg)
 
 You can also install Dangerzone for Mac using [Homebrew](https://brew.sh/): `brew install --cask dangerzone`
 
@@ -24,7 +24,7 @@ You can also install Dangerzone for Mac using [Homebrew](https://brew.sh/): `bre
 
 ### Windows
 
-- Download [Dangerzone 0.6.0 for Windows](https://github.com/freedomofpress/dangerzone/releases/download/v0.6.0/Dangerzone-0.6.0.msi)
+- Download [Dangerzone 0.5.1 for Windows](https://github.com/freedomofpress/dangerzone/releases/download/v0.5.1/Dangerzone-0.5.1.msi)
 
 > **Note**: you will also need to install [Docker Desktop](https://www.docker.com/products/docker-desktop/).
 > This program needs to run alongside Dangerzone at all times, since it is what allows Dangerzone to