ci: remove doc action and travis config (#309)

* ci: remove doc action and travis config

Signed-off-by: ekexium <ekexium@gmail.com>

* ci: deny warnings

Signed-off-by: ekexium <ekexium@gmail.com>

Author: ekexium

.github/workflows/doc.yml

@@ -1,3 +1,5 @@
+export RUSTFLAGS=-Dwarnings
+
 .PHONY: default check unit-test integration-tests test doc docker-pd docker-kv docker all
 
 default: check

.travis.yml

@@ -3,8 +3,6 @@
 [![Docs](https://docs.rs/tikv-client/badge.svg)](https://docs.rs/tikv-client)
 [![Build Status](https://travis-ci.org/tikv/client-rust.svg?branch=master)](https://travis-ci.org/tikv/client-rust)
 
-[Nightly docs](https://www.tikv.dev/doc/rust-client/tikv_client/)
-
 This crate provides an easy-to-use client for [TiKV](https://github.com/tikv/tikv), a distributed, transactional key-value database written in Rust.
 
 This crate lets you connect to a TiKV(>= `v5.0.0`) cluster and use either a transactional or raw (simple get/put style without transactional consistency guarantees) API to access and update your data.