Update zxing lib, to hopefully fix a an autobug

app/build.gradle

@@ -134,8 +134,9 @@ dependencies {
     // https://firebase.google.com/docs/android/setup#available-libraries
 
     // barcode support
-    // implementation('com.google.zxing:core:3.4.0')
-    implementation('com.journeyapps:zxing-android-embedded:3.6.0')
+    // per https://github.com/journeyapps/zxing-android-embedded for support of android version 22
+    implementation('com.journeyapps:zxing-android-embedded:4.1.0') { transitive = false }
+    implementation 'com.google.zxing:core:3.3.0'
 
     implementation project(':geeksville-androidlib')
 }

app/src/main/AndroidManifest.xml

@@ -4,6 +4,9 @@
     xmlns:tools="http://schemas.android.com/tools"
     tools:ignore="GoogleAppIndexingWarning">
 
+    <!-- per https://github.com/journeyapps/zxing-android-embedded to force support for build 22 -->
+    <uses-sdk tools:overrideLibrary="com.google.zxing.client.android" />
+
     <uses-permission android:name="android.permission.BLUETOOTH" />
     <uses-permission android:name="android.permission.BLUETOOTH_ADMIN" />