v0.16.0

• Bumped minimum Go version to 1.20.
• Breaking change (util) Moved package to go.mau.fi/util
• (event) Removed MSC2716 historical field in the m.room.power_levels event content struct.
• (bridge) Added --version-json flag to print bridge version info as JSON.
• (appservice) Added option to use custom transaction handler for websocket mode.