Upgrade to build tools 29.0.3

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

app/build.gradle

@@ -7,7 +7,7 @@ apply from: 'nonnull.gradle'
 final def keystorePropertiesFile = rootProject.file("keystore.properties")
 
 android {
-    buildToolsVersion '29.0.2'
+    buildToolsVersion '29.0.3'
     compileOptions {
         sourceCompatibility JavaVersion.VERSION_1_8
         targetCompatibility JavaVersion.VERSION_1_8