Prepare release

Bump version to 4.BETA.0

Merge pull request discord-jda#867 from DV8FromTheWorld/release/3.8.2

Release 3.8.2

Merge pull request discord-jda#794 from DV8FromTheWorld/release-3.8.1

Release 3.8.1

Merge pull request discord-jda#768 from DV8FromTheWorld/release/3.8.0

Release 3.8.0

Closes discord-jda#512, discord-jda#602, discord-jda#625, discord-jda#661, discord-jda#691, discord-jda#699, discord-jda#733, discord-jda#763, discord-jda#767

Release 3.6.0

Merge pull request discord-jda#620 from DV8FromTheWorld/release/3.5.1

Release 3.5.1