gitsigns is broken recently

[stonemaster]

Pressing hb for example on a code snippet doesn't trigger gitsigns anymore with blame information but shows the following error message:

Error executing vim.schedule lua callback: ...ithub.com/lewis6991/gitsigns.nvim/lua/gitsigns/async.lua:67: The coroutine failed with this message: ...hub.com/lewis6991/gitsigns.nvim/lua/gitsi
gns/actions.lua:764: attempt to index local 'opts' (a boolean value)                                                                                                                           
stack traceback:                                                                                                                                                                               
        ...hub.com/lewis6991/gitsigns.nvim/lua/gitsigns/actions.lua: in function <...hub.com/lewis6991/gitsigns.nvim/lua/gitsigns/actions.lua:749>                                             
stack traceback:                                                                                                                                                                               
        [C]: in function 'error'                                                                                                                                                               
        ...ithub.com/lewis6991/gitsigns.nvim/lua/gitsigns/async.lua:67: in function <...ithub.com/lewis6991/gitsigns.nvim/lua/gitsigns/async.lua:62>                                           
Error executing vim.schedule lua callback: ...ithub.com/lewis6991/gitsigns.nvim/lua/gitsigns/async.lua:67: The coroutine failed with this message: ...hub.com/lewis6991/gitsigns.nvim/lua/gitsi
gns/actions.lua:764: attempt to index local 'opts' (a boolean value)  

I know that it was working some time ago but unfortunately don't know when it broke & what caused it :-)