Bump org.osmdroid:osmdroid-android from 6.1.18 to 6.1.20

Bumps [org.osmdroid:osmdroid-android](https://github.com/osmdroid/osmdroid) from 6.1.18 to 6.1.20.
- [Release notes](https://github.com/osmdroid/osmdroid/releases)
- [Changelog](https://github.com/osmdroid/osmdroid/blob/master/CHANGELOG.md)
- [Commits](osmdroid/osmdroid@osmdroid-parent-6.1.18...osmdroid-parent-6.1.20)

---
updated-dependencies:
- dependency-name: org.osmdroid:osmdroid-android
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

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

app/build.gradle

@@ -209,7 +209,7 @@ dependencies {
     storeImplementation 'com.google.android.gms:play-services-code-scanner:16.1.0'
 
     // Dependencies for open version.
-    openImplementation 'org.osmdroid:osmdroid-android:6.1.18'
+    openImplementation 'org.osmdroid:osmdroid-android:6.1.20'
     openImplementation 'com.journeyapps:zxing-android-embedded:4.3.0'
 
     if (props.getProperty("hydra.debug.leaks").toBoolean()) {