Build(deps): Bump exoplayerVersion from 2.18.3 to 2.18.4

Bumps `exoplayerVersion` from 2.18.3 to 2.18.4.

Updates `com.google.android.exoplayer:exoplayer` from 2.18.3 to 2.18.4
- [Release notes](https://github.com/google/ExoPlayer/releases)
- [Changelog](https://github.com/google/ExoPlayer/blob/release-v2/RELEASENOTES.md)
- [Commits](https://github.com/google/ExoPlayer/compare/r2.18.3...r2.18.4)

Updates `com.google.android.exoplayer:extension-okhttp` from 2.18.3 to 2.18.4
- [Release notes](https://github.com/google/ExoPlayer/releases)
- [Changelog](https://github.com/google/ExoPlayer/blob/release-v2/RELEASENOTES.md)
- [Commits](https://github.com/google/ExoPlayer/compare/r2.18.3...r2.18.4)

---
updated-dependencies:
- dependency-name: com.google.android.exoplayer:exoplayer
  dependency-type: direct:production
  update-type: version-update:semver-patch
- dependency-name: com.google.android.exoplayer:extension-okhttp
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

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

build.gradle

@@ -16,7 +16,7 @@ buildscript {
         workRuntime = "2.8.0"
         fidoVersion = "4.1.0-patch1"
         checkerVersion = "3.21.2"
-        exoplayerVersion = "2.18.3"
+        exoplayerVersion = "2.18.4"
         documentScannerVersion = "1.0.1"
         roomVersion = "2.5.0"