feat: replace mock skywalking server with real one in CI

[Sn0rt]

Description

file t/plugin/skywalking-logger.t

add_block_preprocessor(sub {
    my ($block) = @_;

    my $http_config = $block->http_config // <<_EOC_;

    server {
        listen 1986;
        server_tokens off;

        location /v3/logs {
            content_by_lua_block {
                local core = require("apisix.core")

                core.log.warn(core.json.encode(core.request.get_body(), true))
            }
        }
    }
_EOC_