build: uprev AGP and add AS version note to README

Signed-off-by: Harsh Shandilya <me@msfjarvis.dev>

README.md

@@ -1,3 +1,5 @@
 # Claw for [lobste.rs](https://lobste.rs)
 
 Android app for read-only access to [lobste.rs](https://lobste.rs) community, built with [Jetpack Compose](https://developer.android.com/jetpack/compose).
+
+Requires Android Studio 2020.3.1 to work.

buildSrc/buildDependencies.gradle

@@ -1,5 +1,5 @@
 rootProject.ext.versions = [
-  agp: '4.2.0-alpha16',
+  agp: '7.0.0-alpha01',
   daggerHilt: '2.30.1-alpha',
   kotlin: '1.4.10',
 ]