fix stdlib warning

app/build.gradle

@@ -116,7 +116,6 @@ dependencies {
     def room_version = '2.3.0'
 
     implementation fileTree(dir: 'libs', include: ['*.jar'])
-    implementation "org.jetbrains.kotlin:kotlin-stdlib:$kotlin_version"
     implementation 'androidx.appcompat:appcompat:1.3.0'
     implementation 'androidx.core:core-ktx:1.5.0'
     implementation 'androidx.fragment:fragment-ktx:1.3.4'

geeksville-androidlib

@@ -1 +1 @@
-Subproject commit 30087d5ee497f17b210b69aab7f20e369a294d20
+Subproject commit b84afd618d7e80a7ff26d70e0cc5c2f418da7ff6