Drop OTP 21 support in rebar.config and README (erlang-ls#1217)

Fix support for renaming modules (erlang-ls#1199)

The textDocument parameter in a TextDocumentEdit must contain a version, even if null (see the OptionalVersionedTextDocumentIdentifier definition from the LSP specification). Without it, some editors (most notably VS Code) would reject the edits

Revert "Precompute list of enabled diagnostics" (erlang-ls#1197)

This reverts commit 2f6decd.

This change introduced a regression in the debugger, preventing it from starting.
The `els_dap` escript invokes the `els_config` initialization procedure
(see erlang-ls@4b475b0),
but the new version of the initialization depends on the `els_diagnostics` module,
which is part of the `els_lsp` application, not included in the `els_dap` escript.

For now simply reverting the change, but we should revisit the application structure.
The original idea was for an application to contain the implementation of the JSON-RPC protocol
and for the `els_dap` and `els_lsp` to utilize that as a dependency. That never really happened
and the current application split in Erlang LS in its current form feels a bit arbitrary.
One may argue that Erlang LS could get rid of the umbrella structure and be a single application.

Avoid compiler_diagnostics crash in case module name is invalid (erla…

…ng-ls#1191)

Invalid syntax on the module attribute can cause a crash.

Merge pull request erlang-ls#1151 from garazdawi/lukas/revert-unicode…

…-support

Revert unicode support

Merge pull request erlang-ls#1150 from erlang-ls/1149-version-should-…

…exit-0

[erlang-ls#1149] Exit with 0 on --version

Merge pull request erlang-ls#1147 from garazdawi/lukas/fix-unicode-os…

…-cmd

Fix unicode output via stdout

Merge pull request erlang-ls#1108 from erlang-ls/1107-do-not-always-e…

…xpect-params

[erlang-ls#1107] Shutdown request does not include parameters

Merge pull request erlang-ls#1079 from erlang-ls/diagnostics-codes-te…

…lemetry

Send telemetry notification with compiler diagnostic codes

Merge pull request erlang-ls#1071 from erlang-ls/1070-fix-distributio…

…n-when-no-cookie-is-specified

[erlang-ls#1070] Only set the cookie if the provided one is a valid one