build: bump minor dependencies versions

Change-Id: I8721fedb4dd1baa2dc8e0ed58c2780b19658af21
diff --git a/ring-android/app/build.gradle b/ring-android/app/build.gradle
index d36be08..bb91e13 100644
--- a/ring-android/app/build.gradle
+++ b/ring-android/app/build.gradle
@@ -4,7 +4,7 @@
 
 android {
     compileSdkVersion 27
-    buildToolsVersion "26.0.3"
+    buildToolsVersion '27.0.3'
 
     defaultConfig {
         minSdkVersion 18
@@ -36,6 +36,10 @@
         targetCompatibility JavaVersion.VERSION_1_8
     }
     buildTypes {
+        debug {
+            minifyEnabled true
+            proguardFiles getDefaultProguardFile('proguard-android-optimize.txt'), 'proguard-rules.pro'
+        }
         release {
             minifyEnabled true
             proguardFiles getDefaultProguardFile('proguard-android-optimize.txt'), 'proguard-rules.pro'
@@ -108,7 +112,7 @@
     implementation 'com.github.bumptech.glide:glide:3.8.0'
 
     // RxAndroid
-    implementation 'io.reactivex.rxjava2:rxandroid:2.0.1'
+    implementation 'io.reactivex.rxjava2:rxandroid:2.0.2'
 
     withFirebaseImplementation 'com.google.firebase:firebase-messaging:11.8.0'
 }