update support library

OpenKeychain/build.gradle

@@ -7,12 +7,12 @@ dependencies {
     // NOTE: libraries are pinned to a specific build, see below
 
     // from local Android SDK
-    implementation 'com.android.support:support-v4:27.1.1'
-    implementation 'com.android.support:appcompat-v7:27.1.1'
-    implementation 'com.android.support:design:27.1.1'
-    implementation 'com.android.support:recyclerview-v7:27.1.1'
-    implementation 'com.android.support:cardview-v7:27.1.1'
-    implementation 'com.android.support:support-annotations:27.1.1'
+    implementation 'com.android.support:support-v4:28.0.0'
+    implementation 'com.android.support:appcompat-v7:28.0.0'
+    implementation 'com.android.support:design:28.0.0'
+    implementation 'com.android.support:recyclerview-v7:28.0.0'
+    implementation 'com.android.support:cardview-v7:28.0.0'
+    implementation 'com.android.support:support-annotations:28.0.0'
 
     // JCenter etc.
     implementation 'com.journeyapps:zxing-android-embedded:3.4.0'