Build(deps): Bump com.github.bitfireAT:dav4jvm from 2.1.3 to 2.2.1

Bumps [com.github.bitfireAT:dav4jvm](https://github.com/bitfireAT/dav4jvm) from 2.1.3 to 2.2.1.
- [Changelog](https://github.com/bitfireAT/dav4jvm/blob/main/CHANGELOG.md)
- [Commits](bitfireAT/dav4jvm@2.1.3...2.2.1)

---
updated-dependencies:
- dependency-name: com.github.bitfireAT:dav4jvm
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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

app/build.gradle

@@ -190,7 +190,7 @@ dependencies {
     implementation 'androidx.swiperefreshlayout:swiperefreshlayout:1.1.0'
     androidTestImplementation "androidx.work:work-testing:${workVersion}"
     implementation 'com.google.android.flexbox:flexbox:3.0.0'
-    implementation ('com.github.bitfireAT:dav4jvm:2.1.3', {
+    implementation ('com.github.bitfireAT:dav4jvm:2.2.1', {
         exclude group: 'org.ogce', module: 'xpp3'	// Android comes with its own XmlPullParser
     })
     implementation 'org.conscrypt:conscrypt-android:2.5.2'