Merge branch 'upgrade-dependencies' into 'master'

bramble-android/build.gradle

bramble-android/witness.gradle

bramble-core/build.gradle

bramble-core/witness.gradle

bramble-java/build.gradle

bramble-java/witness.gradle

briar-android/build.gradle

briar-android/proguard-rules.txt

...iarproject/briar/android/reporting/BriarReportSender.java

...iarproject/briar/android/reporting/DevReportActivity.java

briar-android/src/main/res/xml/panic_preferences.xml

briar-android/src/main/res/xml/settings.xml

briar-android/witness.gradle

briar-core/build.gradle

briar-core/witness.gradle

build.gradle

gradle.properties

libs/gradle-witness.jar

update-dependency-pinning.sh