Way to update config before dap.continue

[s1n7ax]

Problem Statement

Running a java applications requires set dap.configurations.java to be set. However this has to be resolved by communicating with the JDTLS.

resolve main classes -> resolve class paths for main classes -> create dap config

Configuration can be done LspAttach event but when updated the change will not reflect. So good option would be to configure it just before running.

Possible Solutions

Similar to dap.adapters, accept functions for dap.configurations

dap.configurations.java = function(on_config)
    -- generate the configuration
    on_config(java_dap_config)
end

Considered Alternatives

No response

[mfussenegger]

There are now configuration providers to do something like this.

See #1237 and for an example implementation https://github.com/mfussenegger/nvim-jdtls/pull/659/files