build(deps): bump kotlin_version in /example/android

Bumps `kotlin_version` from 1.6.10 to 1.6.20.

Updates `kotlin-gradle-plugin` from 1.6.10 to 1.6.20
- [Release notes](https://github.com/JetBrains/kotlin/releases)
- [Changelog](https://github.com/JetBrains/kotlin/blob/v1.6.20/ChangeLog.md)
- [Commits](https://github.com/JetBrains/kotlin/compare/v1.6.10...v1.6.20)

Updates `kotlin-stdlib-jdk7` from 1.6.10 to 1.6.20
- [Release notes](https://github.com/JetBrains/kotlin/releases)
- [Changelog](https://github.com/JetBrains/kotlin/blob/v1.6.20/ChangeLog.md)
- [Commits](https://github.com/JetBrains/kotlin/compare/v1.6.10...v1.6.20)

---
updated-dependencies:
- dependency-name: org.jetbrains.kotlin:kotlin-gradle-plugin
  dependency-type: direct:production
  update-type: version-update:semver-patch
- dependency-name: org.jetbrains.kotlin:kotlin-stdlib-jdk7
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <support@github.com>

 buildscript {
 buildscript {
-    ext.kotlin_version = '1.6.10'
+    ext.kotlin_version = '1.6.20'
     repositories {
     repositories {
         google()
         google()
         mavenCentral()
         mavenCentral()