version bump to 2.12.12

fastlane changelog version codes now use the highest version code after abi split (the F-Droid website displays that one)

build.gradle

@@ -95,8 +95,8 @@ android {
     defaultConfig {
         minSdkVersion 21
         targetSdkVersion 33
-        versionCode 42076
+        versionCode 42077
-        versionName "2.12.12-beta.3"
+        versionName "2.12.12"
         archivesBaseName += "-$versionName"
         applicationId "eu.siacs.conversations"
         resValue "string", "applicationId", applicationId