v0.9.0a: upgrade gradle plugin and R8 config

android/proguard-rules.pro

@@ -2,6 +2,10 @@
 -keepnames class com.shatteredpixel.** { *; }
 -keepnames class com.watabou.** { *; }
 
+# keep members of classes that are instantiated via reflection
+-keepclassmembers class * extends com.watabou.glscripts.Script
+-keepclassmembers class * implements com.watabou.utils.Bundlable
+
 # retained to support meaningful stack traces
 # note that the mapping file must be referenced in order to make sense of line numbers
 # mapping file can be found in core/build/outputs/mapping after running a release build

build.gradle

@@ -4,9 +4,7 @@ buildscript {
         jcenter()
     }
     dependencies {
-        //FIXME the version of R8 coming with gradle plugin 4.0.0 causes serious problems
-        //noinspection GradleDependency
-        classpath 'com.android.tools.build:gradle:3.6.4'
+        classpath 'com.android.tools.build:gradle:4.0.2'
     }
 }