Bump com.google.zxing:core from 3.5.3 to 3.5.4 in /android-refimpl-app

Bumps [com.google.zxing:core](https://github.com/zxing/zxing) from 3.5.3 to 3.5.4.
- [Release notes](https://github.com/zxing/zxing/releases)
- [Changelog](https://github.com/zxing/zxing/blob/master/CHANGES)
- [Commits](zxing/zxing@zxing-3.5.3...zxing-3.5.4)

---
updated-dependencies:
- dependency-name: com.google.zxing:core
  dependency-version: 3.5.4
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <[email protected]>

Author: dependabot[bot]

android-refimpl-app/app/build.gradle

@@ -309,7 +309,7 @@ dependencies {
     implementation('com.mikepenz:material-design-iconic-typeface:2.2.0.5@aar') {
         exclude group: 'com.android.support'
     }
-    implementation('com.google.zxing:core:3.5.3') {
+    implementation('com.google.zxing:core:3.5.4') {
         exclude group: 'com.android.support'
     }
     //