added out-of-date warning in lineageos install

content/post/lineageos_pixel3a.md

@@ -23,6 +23,10 @@ with a custom recovery to utilize for this purpose!
 {{< /thumbgallery >}}
 
 <!--more-->
+{{< admonition warning "Out of Date" >}}
+This guide is now out of date since LineageOS officially supports the Pixel 3a,
+see more here: <https://wiki.lineageos.org/devices/sargo/install>
+{{< /admonition >}}
 # Thank You
 
 Before going on any further, I'd like to take a moment to give my sincere thanks